An Introduction to Web Workers

An Introduction to Web Workers

Learn how to use web workers in JavaScript to create parallel programming and perform multiple operations simultaneously rather than interleaving them.

Learn how to use web workers in JavaScript to create parallel programming and perform multiple operations simultaneously rather than interleaving them.

Web workers enable developers to benefit from parallel programming in JavaScript. Parallel programming lets us run different computations at the same time. Let’s see how we benefit from doing tasks in parallel as humans to help us understand the value of web workers.

Let’s imagine that each one of us runs a tech blog. We work by ourselves and are responsible for coding a demo app, writing about the app development process, and creating assets for the post (like diagrams, images, or logos). That’s a heavy task pipeline to handle by ourselves. Coding the app and writing the content are interconnected since the experience of writing the code motivates writing the content. However, creating assets is something that we could delegate to someone else.

Let’s say that we have a group of friends that are talented designers. They agree to create the assets for us. All that they ask is for us to message them a description or sketch of the asset and they will reply back with a cool professional version of it when they are done. Now, we only need to focus on coding, writing, and integrating the assets of the designers once they message us.

This will give us a huge productivity boost. Initially, we were being blocked from coding and writing whenever we had to design assets. The completion of a blog post would have taken much longer if we were to work alone than if we were to delegate one task to a designer friend.

The design team handles the task asynchronously on their own pipeline. The design team acts exactly how a web worker acts in JavaScript applications. JavaScript is a single-threaded language. As such, running expensive logic in the main thread can block it and make our JavaScript application seem slow or unresponsive. Using web workers, we can create a separate thread to run any logic without interrupting the main thread.

[“Web workers in JavaScript allows us to create parallel programming to perform multiple operations simultaneously rather than interleaving them.”> [“Web workers in JavaScript allows us to create parallel programming to perform multiple operations simultaneously rather than interleaving them.”
Let’s explore what we need to know to make use of web workers in JavaScript and what benefits it brings to a web application.
[“Web workers in JavaScript allows us to create parallel programming to perform multiple operations simultaneously rather than interleaving them.”> [“Web workers in JavaScript allows us to create parallel programming to perform multiple operations simultaneously rather than interleaving them.”> [“Web workers in JavaScript allows us to create parallel programming to perform multiple operations simultaneously rather than interleaving them.”> [“Web workers in JavaScript allows us to create parallel programming to perform multiple operations simultaneously rather than interleaving them.”## Why use JavaScript Web Workers?

Let’s expand a bit more on what Jason Miller explained in his tweets.

In JavaScript, we can create parallel programming to perform multiple operations simultaneously using web workers. Web workers let us create background threads that are separate from the main execution thread, where we usually run our user interface logic. The core advantage of this workload separation is that we can run expensive operations within an isolated thread without interrupting or affecting the responsiveness and usability of the main thread. When the background thread completes its task it seamlessly notifies the main thread about the results through an event that is managed through regular JavaScript event handling.

[“Web workers in JavaScript allows us to create parallel programming to perform multiple operations simultaneously rather than interleaving them.”> [“Web workers in JavaScript allows us to create parallel programming to perform multiple operations simultaneously rather than interleaving them.”#### Tweet This
[“Web workers in JavaScript allows us to create parallel programming to perform multiple operations simultaneously rather than interleaving them.”> [“Web workers in JavaScript allows us to create parallel programming to perform multiple operations simultaneously rather than interleaving them.”
Web workers effectively enable a form of multi-threading in JavaScript with some restrictions such as not being able to access the DOM and not having access to the web worker’s parent page (the page that created it). With that in mind, let’s learn next how we can create web workers.

Setting Up a Development Environment

Getting hands-on with web workers will help us understand them better! For the purpose of this blog post, we’ll be running the sample code within a CodeSandbox project. It’s easy to bootstrap and run a vanilla JavaScript project there. Please, follow these steps:

<html>

<head>
    <title>Parcel Sandbox</title>
    <meta charset="UTF-8" />
</head>

<body>
    <div id="app"></div>

    <script src="src/main.js"></script>

</body>

</html>

We’ll soon learn why we are creating these files. CodeSandbox uses ParcelJS to bundle the JavaScript application easily.

[“Web workers in JavaScript allows us to create parallel programming to perform multiple operations simultaneously rather than interleaving them.”## Creating Web Workers

To create a web worker, we use the [Worker()](https://developer.mozilla.org/en-US/docs/Web/API/Worker/Worker "Worker()") constructor from the Web Workers API. The Worker() constructor has the following signature:

Worker(aURL, options);


aURL is a string that represents the URL of the script that we want the worker to execute.

options is an object to customize the Worker instance. The allowed options are type, credentials, and name. We don’t need to configure them for the scope of this post.

In practice, we instantiate a web worker in the main thread. The main thread could be represented by a JavaScript file, for example, main.js, that is the entry point to the application. The web worker thread could be represented by another file, for example, worker.js. main.js then creates a new Worker using the worker.js file. Let’s see this in action.

Let’s open src/main.js in our project and populate it with the following code:

// src/main.js

const worker = new Worker("../src/worker.js");


In the code above, worker becomes a Worker instance that will execute the script on worker.js.

[“Web workers in JavaScript allows us to create parallel programming to perform multiple operations simultaneously rather than interleaving them.”
That’s it for the creation of a web worker! We effectively now have two threads available in our application: main and worker. Next, we’ll learn how to communicate between threads.

Sending Messages To and From a Web Worker

In the introduction, we discussed how the internal collaboration between our Content and Design teams at Auth0 resemble the interaction between threads using web workers in JavaScript. In our case, a Content Engineer represents the main thread and the Designer represents the worker thread. How would the main thread ping the worker thread and vice versa? We do that through the [postMessage()](https://developer.mozilla.org/en-US/docs/Web/API/Worker/postMessage "postMessage()") method and the [onmessage](https://developer.mozilla.org/en-US/docs/Web/API/Worker/onmessage "onmessage") event handler from the Web Workers API.

Let’s use the classic Marco Polo game to see this communication in action. In this game, one player shouts “Marco!” and the other player must reply “Polo!”. Within our context we want to do the following:

  1. main.js and worker.js are on standby listening for any message between each other.
  2. main.js sends a message to worker.js: "Marco!".
  3. worker.js gets the message from main.js and replies: "Polo!".
  4. Step 2 and Step 3 are repeated infinitely.

Step 1: Listen for Messages

The Worker.onmessage event handler let us listen for messages between the threads. The signature of this Worker event handler property is as follows:

myWorker.onmessage = e => {
  // Event handler logic
};


The function assigned to onmessage is called when a message event occurs.

To set this up in main.js, we use the Worker instance we created:

// src/main.js

const worker = new Worker("../src/worker.js");

worker.onmessage = e => {};


To set this up in the web worker thread represented by worker.js, we use the onmessage property directly:

// src/worker.js

onmessage = e => {};


How do we access the message data that is being sent? The message payload can be accessed from the message event’s data property.

Let’s update our code as follows:

// src/main.js

const worker = new Worker("../src/worker.js");

worker.onmessage = e => {
  const message = e.data;
  console.log(`[From Worker]: ${message}`);
};

// src/worker.js

onmessage = e => {
  const message = e.data;
  console.log(`[From Main]: ${message}`);
};


Let’s save our work for each file. On CodeSandbox, we can use CMD + S or CTRL + S to save each file.

We got our threads listening for messages between each other. Next, let’s learn how to send messages.

Step 2: Send a Message from Main Thread to Worker Thread

To send messages, we rely on the Worker.postMessage() method:

worker.postMessage(message);


The postMessage() takes a single parameter representing the data that we want to send. This data may be any value or JavaScript object handled by the structured clone algorithm. As noted by MDN, the structured clone algorithm is an algorithm defined by the HTML5 specification for copying complex JavaScript objects. Why do we need to rely on this algorithm? Data transferred through web workers is passed as a copy, not as a reference.

With an understanding of how postMessage() work, let’s use this method to send a message from the main thread to the worker thread:

// src/main.js

const worker = new Worker("../src/worker.js");

worker.onmessage = e => {
  const message = e.data;
  console.log(`[From Worker]: ${message}`);
};

worker.postMessage("Marco!");


Let’s save our work and open the application preview on its own tab. This can be done by clicking on the Open In New Window button present in the navigation bar of the embedded browser:

In the new preview browser tab, let’s open the browser developer console and refresh the page. We should see the following output:

// [From Main]: Marco!


This output in the console confirms that our web worker is listening and reacting to the message event sent from main.js. Now, we need to reverse the communication. We need to send a message reply from worker.js to main.js.

Step 3: Send a Message from Worker Thread to Main Thread

This will be quick. We need to use the postMessage() method in the onmessage event handler in worker.js:

// src/worker.js

onmessage = e => {
  const message = e.data;
  console.log(`[From Main]: ${message}`);

  postMessage("Polo!");
};


Let’s save our work and refresh the preview browser tab. In the console, we should now see the following output:

// [From Main]: Marco!
// [From Worker]: Polo!


We have achieved bi-directional communication between threads, but the communication is short-lived. Let’s make this multi-threaded Marco Polo game run infinitely.

Step 4: Send Messages Between Main and Worker Infinitely

We are going to keep the communication between threads going endlessly. To better pace the back and forth, we are going to rely on [setTimeout()](https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/setTimeout "setTimeout()") to delay messaging by 3 seconds.

To start, when main.js gets a message from worker.js, it replies back after 3 seconds:

// src/main.js

const worker = new Worker("../src/worker.js");

worker.onmessage = e => {
  const message = e.data;
  console.log(`[From Worker]: ${message}`);

  const reply = setTimeout(() => worker.postMessage("Marco!"), 3000);
};

worker.postMessage("Marco!");


Next, when worker.js gets a message from main.js it also replies back after 3 seconds:

// src/worker.js

onmessage = e => {
  const message = e.data;
  console.log(`[From Main]: ${message}`);

  const reply = setTimeout(() => postMessage("Polo!"), 3000);
};


The 3 seconds delay creates an eye-friendly pause to be able to see the communication calmly in the developer console. What makes this work infinitely is that every handled message event executes a postMessage() response. Before, the worker.onmessage in main.js did not have a reply within its body.

Let’s save our work and head back to the browser preview. Let’s refresh the page. After a few seconds, we should see the following output:

// [From Main]: Marco!
// [From Worker]: Polo!
// [From Main]: Marco!
// [From Worker]: Polo!


Your browser doesn’t support HTML5 video. Here is a instead.

This will go on forever until we close the browser tab running the preview of our application. But, we could also terminate the web worker manually. Let’s see how we can do that next.

Terminating a Web Worker

We can terminate web workers from the main thread immediately or from the worker thread.

From the main thread, we can terminate a web worker by calling the [terminate()](https://developer.mozilla.org/en-US/docs/Web/API/Worker "terminate()") method of the Web Workers API:

worker.terminate();


After terminate() is issued, the web worker is destroyed immediately without any chance of completing any ongoing or pending operations. The web worker is also given no time to clean up. Thus, terminating a web worker abruptly may lead to memory leaks.

We can also terminate a web worker from the worker thread using its own [close](https://developer.mozilla.org/en-US/docs/Web/API/DedicatedWorkerGlobalScope/close "close") method:

close();


Upon calling close(), any queued tasks present in the event loop are discarded and the web worker scope is closed.

Checking the documentation for close() may be confusing at first because there is a version of the [close()](https://developer.mozilla.org/en-US/docs/Web/API/WorkerGlobalScope "close()") method that has been deprecated. The deprecated version belongs to the WorkerGlobalScope interface. In reality, there are two types of web workers that we can create: dedicated and shared web workers. Each web worker type has its own interface, [DedicatedWorkerGlobalScope](https://developer.mozilla.org/en-US/docs/Web/API/DedicatedWorkerGlobalScope "DedicatedWorkerGlobalScope") and [SharedWorkerGlobalScope](https://developer.mozilla.org/en-US/docs/Web/API/SharedWorkerGlobalScope/close "SharedWorkerGlobalScope") respectively. For the scope of this introduction, we’ve used a dedicated web worker under the hood. The difference between these two types of web workers and how and where to use them will be addressed in a future post along with best practices on terminating workers!

Recap

We’ve learned the basics of how to create a web worker. We learned how to effectively send messages between two threads and how to react to those messages. We briefly touched on the subject of terminating web workers. This last task is to be handled with care and deserves a more detailed explanation. Badly terminated web workers may lead to memory leaks in the application.

[“Web workers in JavaScript allows us to create parallel programming to perform multiple operations simultaneously rather than interleaving them.”
What’s left to learn? A lot! Web workers have been around for a long time and they are great at executing expensive logic. This logic will be much more complex than what we’ve done in this blog post. We’d need to learn topics like handling errors, spawning subworkers, using external libraries, and monitoring web workers using developer tools.

Please let me know in the comments how you liked this introduction to web workers and what else you’d like to learn about this handy technology that lets us perform parallel programming in JavaScript.

Introduction New Features in TypeScript 3.7 and How to Use Them

Introduction New Features in TypeScript 3.7 and How to Use Them

The TypeScript 3.7 release is coming soon, and it's going to be a big one.

The target release date is November 5th, and there are some seriously exciting headline features included:

  • Assert signatures.
  • Recursive type aliases.
  • Top-level await.
  • Null coalescing.
  • Optional chaining.

Personally, I'm super excited about this, they're going to whisk away all sorts of annoyances that I've been fighting in TypeScript while building HTTP Toolkit.

If you haven't been paying close attention to the TypeScript development process though, it's probably not clear what half of these mean, or why you should care. Let's talk through all of them.

Assert Signatures

This is a brand-new and little-known TypeScript feature, which allows you to write functions that act like type guards as a side-effect, rather than explicitly returning their boolean result.

It's easiest to demonstrate this with a JavaScript example:

function assertString(input) { 
  if (typeof input === 'string') 
    return; 
  else 
    throw new Error('Input must be a string!'); 
} 
function doSomething(input) { 
  assertString(input); 
  // ... Use input, confident that it's a string 
} 
doSomething('abc'); 
// All good doSomething(123); // Throws an error

This pattern is neat and useful, and you can't use it in TypeScript today.

TypeScript can't know that you've guaranteed the type of input after it's run assertString. Typically, people just make the argument input: string to avoid this, and that's good. But, it also just pushes the type checking problem somewhere else, and in cases where you just want to fail hard, it's useful to have this option available.

Fortunately, soon we will:

// With TS 3.7 
function assertString(input: any): 
	asserts input is string { 
      // <-- the magic 
      if (typeof input === 'string') 
        return; 
      else 
        throw new Error('Input must be a string!'); 
    } 
function doSomething(input: string | number) { 
  assertString(input); 
  // input's type is just 'string' here }

Here assert input is string means that if this function ever returns, TypeScript can narrow the type of input to string, just as if it was inside an if block with a type guard.

To make this safe, that means if the assert statement isn't true then your assert function must either throw an error or not return at all (kill the process, infinite loop, you name it).

That's the basics, but this actually lets you pull some really neat tricks:

// With TS 3.7 
// Asserts that input is truthy, throwing immediately if not: 
function assert(input: any): 
	asserts input { // <-- not a typo 
      if (!input) 
        throw new Error('Not a truthy value'); 
    } 
declare const x: number | string | undefined; 
assert(x); // Narrows x to number | string 
// Also usable with type guarding expressions! 
assert(typeof x === 'string'); 
// Narrows x to string // -- Or use assert in your tests: -- 
const a: Result | Error = doSomethingTestable(); 
expect(a).is.instanceOf(result); 
// 'instanceOf' could 'asserts a is Result' 
expect(a.resultValue).to.equal(123); 
// a.resultValue is now legal // -- Use as a safer ! that throws immediately if 
// you're wrong -- 
function assertDefined<T>(obj: T): 
	asserts obj is NonNullable<T> { 
      if (obj === undefined || obj === null) { 
        throw new Error('Must not be a nullable value'); 
      } 
    } 
declare const x: string | undefined; 
// Gives y just 'string' as a type, could throw elsewhere later: 
const y = x!; 
// Gives y 'string' as a type, or throws immediately if you're wrong: 
assertDefined(x); const z = x; 
// -- Or even update types to track a function's side-effects -- 
type X<T extends string | {}> = { value: T }; 
// Use asserts to narrow types according to side effects: 
function setX<T extends string | {}>(x: X<any>, v: T): 
	asserts x is X<T> { 
      x.value = v; 
    } 
	declare let x: X<any>; 
// x is now { value: any }; 
setX(x, 123); 
// x is now { value: number };

This is still in flux, so don't take it as the definite result, and keep an eye on the pull request if you want the final details.

There's even a discussion there about allowing functions to assert something and return a type, which would let you extend the final example above to track a much wider variety of side effects, but we'll have to wait and see how that plays out.

Top-Level Await

Async/await is amazing and makes promises dramatically cleaner to use.

Unfortunately, though, you can't use them at the top level. This might not be something you care about much in a TS library or application, but if you're writing a runnable script or using TypeScript in a REPL, then this gets super annoying.

It's even worse if you're used to frontend development, since top-level await has been working nicely in the Chrome and Firefox console for a couple of years now.

Fortunately though, a fix is coming. This is actually a general stage-3 JS proposal, so it'll be everywhere else eventually too, but for TS devs 3.7 is where the magic happens.

This one's simple, but let's have another quick demo anyway:


// Your only solution right now for a script that does something async: 
async function doEverything() { 
  ... 
  const response = await fetch('http://example.com'); 
  ... 
} 
  
doEverything(); // <- eugh (could use an IIFE instead, but even more eugh)

With top-level await:

// With TS 3.7: 
// Your script: ... 
const response = await fetch('http://example.com'); 
// ...

There's a notable gotcha here: if you're not writing a script, or using a REPL, don't write this at the top level, unless you really know what you're doing!

It's totally possible to use this to write modules that do blocking async steps when imported. That can be useful for some niche cases, but people tend to assume that their import statement is a synchronous, reliable, and fairly quick operation, and you could easily hose your codebase's startup time if you start blocking imports for complex async processes (even worse, processes that can fail).

This is somewhat mitigated by the semantics of imports of async modules: they're imported and run in parallel, so the importing module effectively waits for Promise.all(importedModules) before being executed.

Rich Harris wrote an excellent piece on a previous version of this spec before that change when imports ran sequentially and this problem was much worse), which makes for good background reading on the risks here if you're interested.

It's also worth noting that this is only useful for module systems that support asynchronous imports. There isn't yet a formal spec for how TS will handle this, but that likely means that a very recent target configuration, and, either ES Modules or Webpack v5 (whose alphas have experimental support), will be used at runtime.

Recursive Type Aliases

If you're ever tried to define a recursive type in TypeScript, you may have run into StackOverflow questions like this: https://stackoverflow.com/questions/47842266/recursive-types-in-typescript.

Right now, you can't. Interfaces can be recursive, but there are limitations to their expressiveness, and type aliases can't. That means right now, you need to combine the two: define a type alias and extract the recursive parts of the type into interfaces. It works, but it's messy, and we can do better.

As a concrete example, this is the suggested type definition for JSON data:

type JSONValue = | string | number | boolean | JSONObject | JSONArray; 
interface JSONObject { [x: string]: JSONValue; } 
interface JSONArray extends Array<JSONValue> { }

That works, but the extra interfaces are only there because they're required to get around the recursion limitation.

Fixing this requires no new syntax; it just removes that restriction, so the below compiles:

// With TS 3.7: 
type JSONValue = | string | number | boolean | { [x: string]: JSONValue } | Array<JSONValue>;

Right now, that fails to compile with Type alias 'JSONValue' circularly references itself. Soon though, soon...

Null Coalescing

Aside from being difficult to spell, this one is quite simple and easy. It's based on a JavaScript stage-3 proposal, which means it'll also be coming to your favorite vanilla JavaScript environment soon (if it hasn't already).

In JavaScript, there's a common pattern for handling default values, and falling back to the first valid result of a defined group. It looks something like this:

// Use the first of firstResult/secondResult which is truthy: 
const result = firstResult || secondResult; 
// Use configValue from provided options if truthy, or 'default' if not: 
this.configValue = options.configValue || 'default';

This is useful in a host of cases, but due to some interesting quirks in JavaScript, it can catch you out. If firstResult or options.configValue can meaningfully be set to false, an empty string or 0, then this code has a bug. If those values are set, then when considered as booleans they're falsy, so the fallback value (secondResult / 'default') is used anyway.

Null coalescing fixes this. Instead of the above, you'll be able to write:

// With TS 3.7: 
// Use the first of firstResult/secondResult which is *defined*: 
const result = firstResult ?? secondResult; 
// Use configSetting from provided options if *defined*, or 'default' if not: 
this.configValue = options.configValue ?? 'default';

?? differs from || in that it falls through to the next value only if the first argument is null or undefined, not falsy. That fixes our bug. If you pass false as firstResult, that will be used instead of secondResult because, while it's falsy, it is still defined, and that's all that's required.

It's simple but super-useful, as it takes away a whole class of bugs.

Optional Chaining

Last but not least, optional chaining is another stage-3 proposal that is making its way into TypeScript.

This is designed to solve an issue faced by developers in every language: how do you get data out of a data structure when some or all of it might not be present?

Right now, you might do something like this:

// To get data.key1.key2, if any level could be null/undefined: 
let result = data ? (data.key1 ? data.key1.key2 : undefined) : undefined; 
// Another equivalent alternative: 
let result = ((data || {}).key1 || {}).key2;

Nasty! This gets much much worse if you need to go deeper, and although the second example works at runtime, it won't even compile in TypeScript, since the first step could be {}, in which case key1 isn't a valid key at all.

This gets still more complicated if you're trying to get into an array, or there's a function call somewhere in this process.

There's a host of other approaches to this, but they're all noisy, messy & error-prone. With optional chaining, you can do this:

// With TS 3.7: 
// Returns the value is it's all defined & non-null, or undefined if not. 
let result = data?.key1?.key2; 
// The same, through an array index or property, if possible: 
array?.[0]?.['key']; 
// Call a method, but only if it's defined: 
obj.method?.(); 
// Get a property, or return 'default' if any step is not defined: 
let result = data?.key1?.key2 ?? 'default';

The last case shows how neatly some of these dovetails together: null coalescing + optional chaining is a match made in heaven.

One gotcha: this will return undefined for missing values, even if they were null, e.g. in cases like (null)?.key (returns undefined). A small point, but one to watch out for if you have a lot of null in your data structures.

That's the lot! That should outline all the essentials for these features, but there are lots of smaller improvements, fixes, and editor support improvements coming too, so take a look at the official roadmap if you want to get into the nitty-gritty.

Angular 8 Pagination Example and Tutorial

Angular 8 Pagination Example and Tutorial

Pagination is the best way to show huge number of records in series for any application. Also showing/fetching thousands of record at one go will affect the performance of the application.

Pagination is the best way to show huge number of records in series for any application. Also showing/fetching thousands of record at one go will affect the performance of the application.

For example, when you search something that returns a large number of records which cannot be shown on a single web page therefore, those records are part into number of pages that can be accessed through links via pagination structure.

So today in this demo we will discuss the simple pagination in Angular 8.

Step 1: Create a basic app with angular cli
ng new angular8-simple-pagination-example

By typing the above command we will see a basic angular app created on the current folder. So move to the created folder by typing **cd angular8-simple-pagination-example/. **You can check the newly created app by typing http://localhost:4200 on the browser.

Step 2: install ngx-pagination pagination dependency from terminal

So run the below command over terminal

npm install ngx-pagination --save

Step 3: Create dummy records for pagination

Now we will create static data to show the pagination. So lets have a look on the code under file **app.component.ts **

import { Component } from '@angular/core';
import {NgxPaginationModule} from 'ngx-pagination';
@Component({
   selector: 'app-root',
   templateUrl: './app.component.html',
   styleUrls: ['./app.component.css']
})
export class AppComponent {
   title = 'simple pagination demo';
   collection = [];
   constructor(){
     for(let i=1;i<=100;i++){
       let Obj = {'name': `Employee Name ${i}`,'code': `EMP00 ${i}`}
       this.collection.push(Obj);
     }
   }
}

In the above file, we can see that inside constructor we have created a loop for created dummy record for 100 employees having employee name & code for showing pagination.

Step 4: Import dependency in app.module.ts

Now let's have a look on the code inside **app.module.ts **where the ngx-pagination module has been imported

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
 
import { NgxPaginationModule } from 'ngx-pagination';
import { AppComponent } from './app.component';
 
@NgModule({
declarations: [
AppComponent
],
imports: [
BrowserModule,
NgxPaginationModule
],
providers: [],
bootstrap: [AppComponent]
})
export class AppModule { }

Step 5: Update view from app.component.html

Now one last step needed to do is, add the below code anywhere inside app.component.html

*  Emp Name | Emp code
 {{item.name}} | {{item.code}} 


Now, we are done with all the needed steps for the pagination in our angular application.

Step 6: Run the app

Run the app over the terminal with npm start and check the app after typing the url http://localhost:4200/.** **A page will open like below:

Conclusion

By following these easy steps we can easily achieve the client side pagination in Angular 8 application. If you want to impliment server side pagination in angular8 Server Side Pagination in Angular Example and Tutorial . You can also find other demos of Angular Sample Application here to start working on enterprise level application. Click here to view more about the pagination package over npm.

Create Simple Login Page using Angular 8 and HTTP Authentication

Create Simple Login Page using Angular 8 and HTTP Authentication

In this article, you'll learn how to setup a simple login page using Angular 8 and Basic HTTP authentication

In this article, you'll learn how to setup a simple login page using Angular 8 and Basic HTTP authentication

Tutorial built with Angular 8.0.2 and the Angular CLI

Angular CLI was used to generate the base project structure with the ng new command, the CLI is also used to build and serve the application. For more info about the Angular CLI see https://angular.io/cli.

Styling of the example app is all done with Bootstrap 4.3, for more info about Bootstrap see https://getbootstrap.com/docs/4.3/getting-started/introduction/.

Running the Angular 8 Basic Authentication Tutorial Example Locally
  1. Install NodeJS and NPM from https://nodejs.org/en/download/.
  2. Download or clone the tutorial project source code from https://github.com/cornflourblue/angular-8-basic-authentication-example
  3. Install all required npm packages by running npm install from the command line in the project root folder (where the package.json is located).
  4. Start the application by running npm start from the
  5. command line in the project root folder, this will build the application
  6. and automatically launch it in the browser on the URL
  7. http://localhost:4200.

NOTE: You can also run the app directly using the Angular CLI command ng serve --open. To do this first install the Angular CLI globally on your system with the command npm install -g @angular/cli.

Running the Tutorial Example with a Real Backend API

The Angular 8 basic authentication example app uses a fake / mock backend by default so it can run in the browser without a real api, to switch to a real backend api you just have to remove or comment out the line below the comment // provider used to create fake backend located in the /src/app/app.module.ts file.

Angular 8 Tutorial Project Structure

The app and code structure of the tutorial mostly follows the best practice recommendations in the official Angular Style Guide, with a few of my own tweaks here and there.

Each feature has it's own folder (home & login), other shared/common code such as services, models, helpers etc are placed in folders prefixed with an underscore _ to easily differentiate them and group them together at the top of the folder structure.

The index.ts files in each folder are barrel files that group the exported modules from a folder together so they can be imported using the folder path instead of the full module path and to enable importing multiple modules in a single import (e.g. import { AuthenticationService, UserService } from '../_services').

Path aliases @app and @environments have been configured in tsconfig.json that map to the /src/app and /src/environments directories. This allows imports to be relative to the app and environments folders by prefixing import paths with aliases instead of having to use long relative paths (e.g. import MyComponent from '../../../MyComponent').

Here are the main project files that contain the application logic, I left out some files that were generated by Angular CLI ng new command that I didn't change.

  • src
  • app
  • _helpers
  • auth.guard.ts
  • basic-auth.interceptor.ts
  • error.interceptor.ts
  • fake-backend.ts
  • index.ts
  • _models
  • user.ts
  • index.ts
  • _services
  • authentication.service.ts
  • user.service.ts
  • index.ts
  • home
  • home.component.html
  • home.component.ts
  • index.ts
  • login
  • login.component.html
  • login.component.ts
  • index.ts
  • app.component.html
  • app.component.ts
  • app.module.ts
  • app.routing.ts
  • environments
  • environment.prod.ts
  • environment.ts
  • index.html
  • main.ts
  • polyfills.ts
  • styles.less
  • package.json
  • tsconfig.json
Auth Guard

Path: /src/app/_helpers/auth.guard.ts

The auth guard is an angular route guard that's used to prevent unauthenticated users from accessing restricted routes, it does this by implementing the CanActivate interface which allows the guard to decide if a route can be activated with the canActivate() method. If the method returns true the route is activated (allowed to proceed), otherwise if the method returns false the route is blocked.

The auth guard uses the authentication service to check if the user is logged in, if they are logged in it returns true from the canActivate() method, otherwise it returns false and redirects the user to the login page.

Angular route guards are attached to routes in the router config, this auth guard is used in app.routing.ts to protect the home page route.

import { Injectable } from '@angular/core';
import { Router, CanActivate, ActivatedRouteSnapshot, RouterStateSnapshot } from '@angular/router';

import { AuthenticationService } from '@app/_services';

@Injectable({ providedIn: 'root' })
export class AuthGuard implements CanActivate {
    constructor(
        private router: Router,
        private authenticationService: AuthenticationService
    ) { }

    canActivate(route: ActivatedRouteSnapshot, state: RouterStateSnapshot) {
        const currentUser = this.authenticationService.currentUserValue;
        if (currentUser) {
            // logged in so return true
            return true;
        }

        // not logged in so redirect to login page with the return url
        this.router.navigate(['/login'], { queryParams: { returnUrl: state.url } });
        return false;
    }
}
Basic Authentication Interceptor

Path: /src/app/_helpers/basic-auth.interceptor.ts

The Basic Authentication Interceptor intercepts http requests from the application to add basic authentication credentials to the Authorization header if the user is logged in.

It's implemented using the HttpInterceptor class included in the HttpClientModule, by extending the HttpInterceptor class you can create a custom interceptor to modify http requests before they get sent to the server.

Http interceptors are added to the request pipeline in the providers section of the _app.module.ts_ file.

import { Injectable } from '@angular/core';
import { HttpRequest, HttpHandler, HttpEvent, HttpInterceptor } from '@angular/common/http';
import { Observable } from 'rxjs';

import { AuthenticationService } from '@app/_services';

@Injectable()
export class BasicAuthInterceptor implements HttpInterceptor {
    constructor(private authenticationService: AuthenticationService) { }

    intercept(request: HttpRequest, next: HttpHandler): Observable> {
        // add authorization header with basic auth credentials if available
        const currentUser = this.authenticationService.currentUserValue;
        if (currentUser && currentUser.authdata) {
            request = request.clone({
                setHeaders: { 
                    Authorization: `Basic ${currentUser.authdata}`
                }
            });
        }

        return next.handle(request);
    }
}
Http Error Interceptor

Path: /src/app/_helpers/error.interceptor.ts

The Error Interceptor intercepts http responses from the api to check if there were any errors. If there is a 401 Unauthorized response the user is automatically logged out of the application, all other errors are re-thrown up to the calling service so an alert with the error can be displayed on the screen.

It's implemented using the HttpInterceptor class included in the HttpClientModule, by extending the HttpInterceptor class you can create a custom interceptor to catch all error responses from the server in a single location.

Http interceptors are added to the request pipeline in the providers section of the app.module.ts file.

import { Injectable } from '@angular/core';
import { HttpRequest, HttpHandler, HttpEvent, HttpInterceptor } from '@angular/common/http';
import { Observable, throwError } from 'rxjs';
import { catchError } from 'rxjs/operators';

import { AuthenticationService } from '@app/_services';

@Injectable()
export class ErrorInterceptor implements HttpInterceptor {
    constructor(private authenticationService: AuthenticationService) { }

    intercept(request: HttpRequest, next: HttpHandler): Observable> {
        return next.handle(request).pipe(catchError(err => {
            if (err.status === 401) {
                // auto logout if 401 response returned from api
                this.authenticationService.logout();
                location.reload(true);
            }

            const error = err.error.message || err.statusText;
            return throwError(error);
        }))
    }
}
Fake Backend Provider

Path: /src/app/_helpers/fake-backend.ts

In order to run and test the Angular application without a real backend API, the example uses a fake backend that intercepts the HTTP requests from the Angular app and send back "fake" responses. This is done by a class that implements the Angular HttpInterceptor interface, for more information on Angular HTTP Interceptors see https://angular.io/api/common/http/HttpInterceptor

The fake backend contains a handleRoute function that checks if the request matches one of the faked routes in the switch statement, at the moment this includes POST requests to the /users/authenticate route for handling authentication, and GET requests to the /users route for getting all users.

Requests to the authenticate route are handled by the authenticate() function which checks the username and password against an array of hardcoded users. If the username and password are correct then an ok response is returned with the user details, otherwise an error response is returned.

Requests to the get users route are handled by the getUsers() function which checks if the user is logged in by calling the new isLoggedIn() helper function. If the user is logged in an ok() response with the whole users array is returned, otherwise a 401 Unauthorized response is returned by calling the new unauthorized() helper function.

If the request doesn't match any of the faked routes it is passed through as a real HTTP request to the backend API.

import { Injectable } from '@angular/core';
import { HttpRequest, HttpResponse, HttpHandler, HttpEvent, HttpInterceptor, HTTP_INTERCEPTORS } from '@angular/common/http';
import { Observable, of, throwError } from 'rxjs';
import { delay, mergeMap, materialize, dematerialize } from 'rxjs/operators';

import { User } from '@app/_models';

const users: User[] = [{ id: 1, username: 'test', password: 'test', firstName: 'Test', lastName: 'User' }];

@Injectable()
export class FakeBackendInterceptor implements HttpInterceptor {
    intercept(request: HttpRequest, next: HttpHandler): Observable> {
        const { url, method, headers, body } = request;

        // wrap in delayed observable to simulate server api call
        return of(null)
            .pipe(mergeMap(handleRoute))
            .pipe(materialize()) // call materialize and dematerialize to ensure delay even if an error is thrown (https://github.com/Reactive-Extensions/RxJS/issues/648)
            .pipe(delay(500))
            .pipe(dematerialize());

        function handleRoute() {
            switch (true) {
                case url.endsWith('/users/authenticate') && method === 'POST':
                    return authenticate();
                case url.endsWith('/users') && method === 'GET':
                    return getUsers();
                default:
                    // pass through any requests not handled above
                    return next.handle(request);
            }    
        }

        // route functions

        function authenticate() {
            const { username, password } = body;
            const user = users.find(x => x.username === username && x.password === password);
            if (!user) return error('Username or password is incorrect');
            return ok({
                id: user.id,
                username: user.username,
                firstName: user.firstName,
                lastName: user.lastName
            })
        }

        function getUsers() {
            if (!isLoggedIn()) return unauthorized();
            return ok(users);
        }

        // helper functions

        function ok(body?) {
            return of(new HttpResponse({ status: 200, body }))
        }

        function error(message) {
            return throwError({ error: { message } });
        }

        function unauthorized() {
            return throwError({ status: 401, error: { message: 'Unauthorised' } });
        }

        function isLoggedIn() {
            return headers.get('Authorization') === `Basic ${window.btoa('test:test')}`;
        }
    }
}

export let fakeBackendProvider = {
    // use fake backend in place of Http service for backend-less development
    provide: HTTP_INTERCEPTORS,
    useClass: FakeBackendInterceptor,
    multi: true
};
User Model

Path: /src/app/_models/user.ts

The user model is a small class that defines the properties of a user.

export class User {
    id: number;
    username: string;
    password: string;
    firstName: string;
    lastName: string;
    authdata?: string;
}
Authentication Service

Path: /src/app/_services/authentication.service.ts

The authentication service is used to login & logout of the Angular app, it notifies other components when the user logs in & out, and allows access the currently logged in user.

RxJS Subjects and Observables are used to store the current user object and notify other components when the user logs in and out of the app. Angular components can subscribe() to the public currentUser: Observable property to be notified of changes, and notifications are sent when the this.currentUserSubject.next() method is called in the login() and logout() methods, passing the argument to each subscriber. The RxJS BehaviorSubject is a special type of Subject that keeps hold of the current value and emits it to any new subscribers as soon as they subscribe, while regular Subjects don't store the current value and only emit values that are published after a subscription is created.

The login() method sends the user credentials to the API via an HTTP POST request for authentication. If successful the user's basic authentication data (base64 encoded username and password) is added to the user object and stored in localStorage to keep the user logged in between page refreshes. The user object is then published to all subscribers with the call to this.currentUserSubject.next(user);.

The basic auth data is used by the basic authentication interceptor above to set the authorization header of http requests made to secure api endpoints.

The constructor() of the service initialises the currentUserSubject with the currentUser object from localStorage which enables the user to stay logged in between page refreshes or after the browser is closed. The public currentUser property is then set to this.currentUserSubject.asObservable(); which allows other components to subscribe to the currentUser Observable but doesn't allow them to publish to the currentUserSubject, this is so logging in and out of the app can only be done via the authentication service.

The currentUserValue getter allows other components an easy way to get the value of the currently logged in user without having to subscribe to the currentUser Observable.

The logout() method removes the current user object from local storage and publishes null to the currentUserSubject to notify all subscribers that the user has logged out.

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { BehaviorSubject, Observable } from 'rxjs';
import { map } from 'rxjs/operators';

import { environment } from '@environments/environment';
import { User } from '@app/_models';

@Injectable({ providedIn: 'root' })
export class AuthenticationService {
    private currentUserSubject: BehaviorSubject;
    public currentUser: Observable;

    constructor(private http: HttpClient) {
        this.currentUserSubject = new BehaviorSubject(JSON.parse(localStorage.getItem('currentUser')));
        this.currentUser = this.currentUserSubject.asObservable();
    }

    public get currentUserValue(): User {
        return this.currentUserSubject.value;
    }

    login(username: string, password: string) {
        return this.http.post(`${environment.apiUrl}/users/authenticate`, { username, password })
            .pipe(map(user => {
                // store user details and basic auth credentials in local storage to keep user logged in between page refreshes
                user.authdata = window.btoa(username + ':' + password);
                localStorage.setItem('currentUser', JSON.stringify(user));
                this.currentUserSubject.next(user);
                return user;
            }));
    }

    logout() {
        // remove user from local storage to log user out
        localStorage.removeItem('currentUser');
        this.currentUserSubject.next(null);
    }
}
User Service

Path: /src/app/_services/user.service.ts

The user service contains a method for getting all users from the api, I included it to demonstrate accessing a secure api endpoint with the http authorization header set after logging in to the application, the auth header is automatically set with basic authentication credentials by the basic authentication interceptor. The secure endpoint in the example is a fake one implemented in the fake backend provider.

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';

import { environment } from '@environments/environment';
import { User } from '@app/_models';

@Injectable({ providedIn: 'root' })
export class UserService {
    constructor(private http: HttpClient) { }

    getAll() {
        return this.http.get(`${environment.apiUrl}/users`);
    }
}
Home Component Template

Path: /src/app/home/home.component.html

The home component template contains html and angular 8 template syntax for displaying a simple welcome message and a list of users from a secure api endpoint.


    #### You're logged in with Angular 8 & Basic HTTP Authentication!!

    
        ###### Users from secure api end point

        

        
            {{user.firstName}} {{user.lastName}}
        
    

Home Component

Path: /src/app/home/home.component.ts

The home component defines an angular 8 component that gets all users from the user service and makes them available to the template via a users array property.

import { Component } from '@angular/core';
import { first } from 'rxjs/operators';

import { User } from '@app/_models';
import { UserService } from '@app/_services';

@Component({ templateUrl: 'home.component.html' })
export class HomeComponent {
    loading = false;
    users: User[];

    constructor(private userService: UserService) { }

    ngOnInit() {
        this.loading = true;
        this.userService.getAll().pipe(first()).subscribe(users => {
            this.loading = false;
            this.users = users;
        });
    }
}
Login Component Template

Path: /src/app/login/login.component.html

The login component template contains a login form with username and password fields. It displays validation messages for invalid fields when the submit button is clicked. The form submit event is bound to the onSubmit() method of the login component.


    
        Username: test

        Password: test
    
    
        #### Angular 8 Basic Auth Login Example

        
            
                
                    Username
                    
                    
                        Username is required

                    
                
                
                    Password
                    
                    
                        Password is required

                    
                
                
                    
                    Login
                
                {{error}}

            
        
    

Login Component

Path: /src/app/login/login.component.ts

The login component uses the authentication service to login to the application. If the user is already logged in they are automatically redirected to the home page.

The loginForm: FormGroup object defines the form controls and validators, and is used to access data entered into the form. The FormGroup is part of the Angular Reactive Forms module and is bound to the login template above with the [formGroup]="loginForm" directive.

import { Component, OnInit } from '@angular/core';
import { Router, ActivatedRoute } from '@angular/router';
import { FormBuilder, FormGroup, Validators } from '@angular/forms';
import { first } from 'rxjs/operators';

import { AuthenticationService } from '@app/_services';

@Component({ templateUrl: 'login.component.html' })
export class LoginComponent implements OnInit {
    loginForm: FormGroup;
    loading = false;
    submitted = false;
    returnUrl: string;
    error = '';

    constructor(
        private formBuilder: FormBuilder,
        private route: ActivatedRoute,
        private router: Router,
        private authenticationService: AuthenticationService
    ) { 
        // redirect to home if already logged in
        if (this.authenticationService.currentUserValue) { 
            this.router.navigate(['/']);
        }
    }

    ngOnInit() {
        this.loginForm = this.formBuilder.group({
            username: ['', Validators.required],
            password: ['', Validators.required]
        });

        // get return url from route parameters or default to '/'
        this.returnUrl = this.route.snapshot.queryParams['returnUrl'] || '/';
    }

    // convenience getter for easy access to form fields
    get f() { return this.loginForm.controls; }

    onSubmit() {
        this.submitted = true;

        // stop here if form is invalid
        if (this.loginForm.invalid) {
            return;
        }

        this.loading = true;
        this.authenticationService.login(this.f.username.value, this.f.password.value)
            .pipe(first())
            .subscribe(
                data => {
                    this.router.navigate([this.returnUrl]);
                },
                error => {
                    this.error = error;
                    this.loading = false;
                });
    }
}
App Component Template

Path: /src/app/app.component.html

The app component template is the root component template of the application, it contains the main nav bar which is only displayed for authenticated users, and a router-outlet directive for displaying the contents of each view based on the current route / path.



    
        Home
        Logout
    




    

App Component

Path: /src/app/app.component.ts

The app component is the root component of the application, it defines the root tag of the app as `` with the selector property of the @Component() decorator.

It subscribes to the currentUser observable in the authentication service so it can reactively show/hide the main navigation bar when the user logs in/out of the application. I didn't worry about unsubscribing from the observable here because it's the root component of the application, the only time the component will be destroyed is when the application is closed which would destroy any subscriptions as well.

The app component contains a logout() method which is called from the logout link in the main nav bar above to log the user out and redirect them to the login page.

import { Component } from '@angular/core';
import { Router } from '@angular/router';

import { AuthenticationService } from './_services';
import { User } from './_models';

@Component({ selector: 'app', templateUrl: 'app.component.html' })
export class AppComponent {
    currentUser: User;

    constructor(
        private router: Router,
        private authenticationService: AuthenticationService
    ) {
        this.authenticationService.currentUser.subscribe(x => this.currentUser = x);
    }

    logout() {
        this.authenticationService.logout();
        this.router.navigate(['/login']);
    }
}
App Module

Path: /src/app/app.module.ts

The app module defines the root module of the application along with metadata about the module. For more info about angular 8 modules check out this page on the official docs site.

This is where the fake backend provider is added to the application, to switch to a real backend simply remove the providers located below the comment // provider used to create fake backend.

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { ReactiveFormsModule } from '@angular/forms';
import { HttpClientModule, HTTP_INTERCEPTORS } from '@angular/common/http';

// used to create fake backend
import { fakeBackendProvider } from './_helpers';

import { AppComponent } from './app.component';
import { appRoutingModule } from './app.routing';

import { BasicAuthInterceptor, ErrorInterceptor } from './_helpers';
import { HomeComponent } from './home';
import { LoginComponent } from './login';

@NgModule({
    imports: [
        BrowserModule,
        ReactiveFormsModule,
        HttpClientModule,
        appRoutingModule
    ],
    declarations: [
        AppComponent,
        HomeComponent,
        LoginComponent
    ],
    providers: [
        { provide: HTTP_INTERCEPTORS, useClass: BasicAuthInterceptor, multi: true },
        { provide: HTTP_INTERCEPTORS, useClass: ErrorInterceptor, multi: true },

        // provider used to create fake backend
        fakeBackendProvider
    ],
    bootstrap: [AppComponent]
})
export class AppModule { }
App Routing Module

Path: /src/app/app.routing.ts

Routing for the Angular app is configured as an array of Routes, each component is mapped to a path so the Angular Router knows which component to display based on the URL in the browser address bar. The home route is secured by passing the AuthGuard to the canActivate property of the route.

The Routes array is passed to the RouterModule.forRoot() method which creates a routing module with all of the app routes configured, and also includes all of the Angular Router providers and directives such as the `` directive. For more information on Angular Routing and Navigation see https://angular.io/guide/router.

import { Routes, RouterModule } from '@angular/router';

import { HomeComponent } from './home';
import { LoginComponent } from './login';
import { AuthGuard } from './_helpers';

const routes: Routes = [
    { path: '', component: HomeComponent, canActivate: [AuthGuard] },
    { path: 'login', component: LoginComponent },

    // otherwise redirect to home
    { path: '**', redirectTo: '' }
];

export const appRoutingModule = RouterModule.forRoot(routes);
Production Environment Config

Path: /src/environments/environment.prod.ts

The production environment config contains variables required to run the application in production. This enables you to build the application with a different configuration for each different environment (e.g. production & development) without updating the app code.

When you build the application for production with the command ng build --prod, the output environment.ts is replaced with environment.prod.ts.

export const environment = {
    production: true,
    apiUrl: 'http://localhost:4000'
};
Development Environment Config

Path: /src/environments/environment.ts

The development environment config contains variables required to run the application in development.

Environment config is accessed by importing the environment object into any Angular service of component with the line import { environment } from '@environments/environment' and accessing properties on the environment object, see the user service for an example.

export const environment = {
    production: false,
    apiUrl: 'http://localhost:4000'
};
Main Index Html File

Path: /src/index.html

The main index.html file is the initial page loaded by the browser that kicks everything off. The Angular CLI (with Webpack under the hood) bundles all of the compiled javascript files together and injects them into the body of the index.html page so the scripts can be loaded and executed by the browser.




    
    Angular 8 - Basic HTTP Authentication Tutorial & Example
    

    
    


    Loading...


Main (Bootstrap) File

Path: /src/main.ts

The main file is the entry point used by angular to launch and bootstrap the application.

import { enableProdMode } from '@angular/core';
import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';

import { AppModule } from './app/app.module';
import { environment } from './environments/environment';

if (environment.production) {
    enableProdMode();
}

platformBrowserDynamic().bootstrapModule(AppModule)
    .catch(err => console.error(err));
Polyfills

Path: /src/polyfills.ts

Some features used by Angular 8 are not yet supported natively by all major browsers, polyfills are used to add support for features where necessary so your Angular 8 application works across all major browsers.

This file is generated by the Angular CLI when creating a new project with the ng new command, I've excluded the comments in the file for brevity.

import 'zone.js/dist/zone';
Global LESS/CSS Styles

Path: /src/styles.less

The global styles file contains LESS/CSS styles that are applied globally throughout the application.

/* You can add global styles to this file, and also import other style files */
a { cursor: pointer }
npm package.json

Path: /package.json

The package.json file contains project configuration information including package dependencies which get installed when you run npm install. Full documentation is available on the npm docs website.

{
    "name": "angular-8-basic-authentication-example",
    "version": "1.0.0",
    "scripts": {
        "ng": "ng",
        "start": "ng serve --open",
        "build": "ng build",
        "test": "ng test",
        "lint": "ng lint",
        "e2e": "ng e2e"
    },
    "private": true,
    "dependencies": {
        "@angular/animations": "~8.0.1",
        "@angular/common": "~8.0.1",
        "@angular/compiler": "~8.0.1",
        "@angular/core": "~8.0.1",
        "@angular/forms": "~8.0.1",
        "@angular/platform-browser": "~8.0.1",
        "@angular/platform-browser-dynamic": "~8.0.1",
        "@angular/router": "~8.0.1",
        "rxjs": "~6.4.0",
        "tslib": "^1.9.0",
        "zone.js": "~0.9.1"
    },
    "devDependencies": {
        "@angular-devkit/build-angular": "~0.800.0",
        "@angular/cli": "~8.0.3",
        "@angular/compiler-cli": "~8.0.1",
        "@angular/language-service": "~8.0.1",
        "@types/node": "~8.9.4",
        "@types/jasmine": "~3.3.8",
        "@types/jasminewd2": "~2.0.3",
        "codelyzer": "^5.0.0",
        "jasmine-core": "~3.4.0",
        "jasmine-spec-reporter": "~4.2.1",
        "karma": "~4.1.0",
        "karma-chrome-launcher": "~2.2.0",
        "karma-coverage-istanbul-reporter": "~2.0.1",
        "karma-jasmine": "~2.0.1",
        "karma-jasmine-html-reporter": "^1.4.0",
        "protractor": "~5.4.0",
        "ts-node": "~7.0.0",
        "tslint": "~5.15.0",
        "typescript": "~3.4.3"
    }
}
TypeScript tsconfig.json

Path: /tsconfig.json

The tsconfig.json file configures how the TypeScript compiler will convert TypeScript into JavaScript that is understood by the browser. More information is available on the TypeScript docs.

Most of the file is unchanged from when it was generated by the Angular CLI, only the paths property has been added to map @app and @environments to the /src/app and /src/environments directories. This allows imports to be relative to the app and environments folders by prefixing import paths with aliases instead of having to use long relative paths (e.g. import MyComponent from '../../../MyComponent').

{
    "compileOnSave": false,
    "compilerOptions": {
        "baseUrl": "./",
        "outDir": "./dist/out-tsc",
        "sourceMap": true,
        "declaration": false,
        "downlevelIteration": true,
        "emitDecoratorMetadata": true,
        "experimentalDecorators": true,
        "module": "esnext",
        "moduleResolution": "node",
        "importHelpers": true,
        "target": "es2015",
        "typeRoots": [
            "node_modules/@types"
        ],
        "lib": [
            "es2018",
            "dom"
        ],
        "paths": {
            "@app/*": ["src/app/*"],
            "@environments/*": ["src/environments/*"]
        }
    }
}

The tutorial code is available on GitHub

Laravel 5.8 Tutorial - How to build user roles and permissions on Laravel 5.8 App

Laravel 5.8 Tutorial - How to build user roles and permissions on Laravel 5.8 App

In this article, you'll learn how to user build roles and permissions on Laravel 5.8 Application. You can do it acl in Laravel 5.8 using spatie composer package. I will explain how to implement User Roles and Permissions(ACL) using spatie/laravel-permission composer package.

In this article, you'll learn how to user build roles and permissions on Laravel 5.8 Application. You can do it acl in Laravel 5.8 using spatie composer package. I will explain how to implement User Roles and Permissions(ACL) using spatie/laravel-permission composer package.

Spatie role permission composer package provide way to create acl in Laravel 5.8. They provide how to assign role to user, how to assign permission to user and how to assign permission assign to roles. I will write step by step creating roles and permissions in Laravel 5.8 application.

Roles and Permissions through you can create several types of users with different role and permission, i mean some user have only see listing of items module, some user can also edit items modules, for delete and etc.

In this examples i created three modules as listed bellow:

  • User Management
  • Role Management
  • Product Management

After register user, you don't have any roles, so you can edit your details and assign admin role to you from User Management. After that you can create your own role with permission like role-list, role-create, role-edit, role-delete, product-list, product-create, product-edit, product-delete. You can check with assign new user and check that.

Step 1: Laravel 5.8 Installation

We are going from scratch so, If you haven't installed Laravel in your system then you can run bellow command and get fresh Laravel project.

composer create-project --prefer-dist laravel/laravel blog

Step 2: Install Composer Packages

Now we require to install Spatie package for ACL, that way we can use it's method. Also we will install form collection package. So Open your terminal and run bellow command.

composer require spatie/laravel-permission
  
composer require laravelcollective/html

Now open config/app.php file and add service provider and aliase.

config/app.php

'providers' => [
	....
	Spatie\Permission\PermissionServiceProvider::class,
	Collective\Html\HtmlServiceProvider::class,
],
'aliases' => [
	....
	'Form' => Collective\Html\FormFacade::class,
	'Html' => Collective\Html\HtmlFacade::class,
],

We can also custom changes on Spatie package, so if you also want to changes then you can fire bellow command and get config file in config/permission.php.

php artisan vendor:publish --provider="Spatie\Permission\PermissionServiceProvider" --tag="config"

Step 3: Create Migrations

In this step we have to create three migrations for as listed bellow tables:

  1. users

  2. products

  3. roles

  4. permissions

  5. model_has_permissions

  6. model_has_roles

  7. role_has_permissions

So, if you install fresh project then you have already users table migration but if you don't have products table, so can create manually and other table can create using Spatie package command, so run bellow command and check migration file also.

php artisan vendor:publish --provider="Spatie\Permission\PermissionServiceProvider" --tag="migrations"
php artisan make:migration create_products_table

users table:

<?php

use Illuminate\Support\Facades\Schema;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Migrations\Migration;

class CreateUsersTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('users', function (Blueprint $table) {
            $table->bigIncrements('id');
            $table->string('name');
            $table->string('email');
            $table->string('password');
            $table->rememberToken();
            $table->timestamps();
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('users');
    }
}

products table:

<?php

use Illuminate\Support\Facades\Schema;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Migrations\Migration;

class CreateProductsTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('products', function (Blueprint $table) {
            $table->bigIncrements('id');
            $table->string('name');
            $table->text('detail');
            $table->timestamps();
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('products');
    }
}

Spatie tables:

<?php

use Illuminate\Support\Facades\Schema;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Migrations\Migration;

class CreatePermissionTables extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        $tableNames = config('permission.table_names');

        Schema::create($tableNames['permissions'], function (Blueprint $table) {
            $table->increments('id');
            $table->string('name');
            $table->string('guard_name');
            $table->timestamps();
        });

        Schema::create($tableNames['roles'], function (Blueprint $table) {
            $table->increments('id');
            $table->string('name');
            $table->string('guard_name');
            $table->timestamps();
        });

        Schema::create($tableNames['model_has_permissions'], function (Blueprint $table) use ($tableNames) {
            $table->integer('permission_id')->unsigned();
            $table->morphs('model');

            $table->foreign('permission_id')
                ->references('id')
                ->on($tableNames['permissions'])
                ->onDelete('cascade');

            $table->primary(['permission_id', 'model_id', 'model_type']);
        });

        Schema::create($tableNames['model_has_roles'], function (Blueprint $table) use ($tableNames) {
            $table->integer('role_id')->unsigned();
            $table->morphs('model');

            $table->foreign('role_id')
                ->references('id')
                ->on($tableNames['roles'])
                ->onDelete('cascade');

            $table->primary(['role_id', 'model_id', 'model_type']);
        });

        Schema::create($tableNames['role_has_permissions'], function (Blueprint $table) use ($tableNames) {
            $table->integer('permission_id')->unsigned();
            $table->integer('role_id')->unsigned();

            $table->foreign('permission_id')
                ->references('id')
                ->on($tableNames['permissions'])
                ->onDelete('cascade');

            $table->foreign('role_id')
                ->references('id')
                ->on($tableNames['roles'])
                ->onDelete('cascade');

            $table->primary(['permission_id', 'role_id']);

            app('cache')->forget('spatie.permission.cache');
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        $tableNames = config('permission.table_names');

        Schema::drop($tableNames['role_has_permissions']);
        Schema::drop($tableNames['model_has_roles']);
        Schema::drop($tableNames['model_has_permissions']);
        Schema::drop($tableNames['roles']);
        Schema::drop($tableNames['permissions']);
    }
}

Now run migration:

php artisan migrate

Step 4: Create Models

In this step we have to create model for User and Product table, so if you get fresh project then you have User Model have so just replace code and other you should create.

app/User.php

<?php
  
namespace App;
  
use Illuminate\Notifications\Notifiable;
use Illuminate\Contracts\Auth\MustVerifyEmail;
use Illuminate\Foundation\Auth\User as Authenticatable;
use Spatie\Permission\Traits\HasRoles;
  
class User extends Authenticatable
{
    use Notifiable;
    use HasRoles;
  
    /**
     * The attributes that are mass assignable.
     *
     * @var array
     */
    protected $fillable = [
        'name', 'email', 'password',
    ];
  
    /**
     * The attributes that should be hidden for arrays.
     *
     * @var array
     */
    protected $hidden = [
        'password', 'remember_token',
    ];
  
    /**
     * The attributes that should be cast to native types.
     *
     * @var array
     */
    protected $casts = [
        'email_verified_at' => 'datetime',
    ];
}

app/Product.php

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Product extends Model
{
    /**
     * The attributes that are mass assignable.
     *	
     * @var array
     */
    protected $fillable = [
        'name', 'detail'
    ];
}

Step 5: Add Middleware

Spatie package provide it's in-built middleware that way we can use it simply and that is display as bellow:

role

permission

So, we have to add middleware in Kernel.php file this way :

app/Http/Kernel.php

....
protected $routeMiddleware = [
	....
	'role' => \Spatie\Permission\Middlewares\RoleMiddleware::class,
	'permission' => \Spatie\Permission\Middlewares\PermissionMiddleware::class,
]
....

Step 6: Create Authentication

In this step we require to create authentication of Laravel 5.8, so laravel provide artisan command to create authentication that way we don't require to create route and controller for login and registration. so run bellow command:

php artisan make:auth

Step 7: Create Routes

We require to add number of route for users module, products module and roles module. In this this route i also use middleware with permission for roles and products route, so add route this way:

routes/web.php

Auth::routes();

Route::get('/home', '[email protected]')->name('home');

Route::group(['middleware' => ['auth']], function() {
    Route::resource('roles','RoleController');
    Route::resource('users','UserController');
    Route::resource('products','ProductController');
});

Step 8: Add Controllers

In this step we have add three controller for users module, products module and roles module so you can create three controller like as bellow:

app/Http/Controllers/UserController.php

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\Http\Controllers\Controller;
use App\User;
use Spatie\Permission\Models\Role;
use DB;
use Hash;

class UserController extends Controller
{
    /**
     * Display a listing of the resource.
     *
     * @return \Illuminate\Http\Response
     */
    public function index(Request $request)
    {
        $data = User::orderBy('id','DESC')->paginate(5);
        return view('users.index',compact('data'))
            ->with('i', ($request->input('page', 1) - 1) * 5);
    }

    /**
     * Show the form for creating a new resource.
     *
     * @return \Illuminate\Http\Response
     */
    public function create()
    {
        $roles = Role::pluck('name','name')->all();
        return view('users.create',compact('roles'));
    }

    /**
     * Store a newly created resource in storage.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return \Illuminate\Http\Response
     */
    public function store(Request $request)
    {
        $this->validate($request, [
            'name' => 'required',
            'email' => 'required|email|unique:users,email',
            'password' => 'required|same:confirm-password',
            'roles' => 'required'
        ]);

        $input = $request->all();
        $input['password'] = Hash::make($input['password']);

        $user = User::create($input);
        $user->assignRole($request->input('roles'));

        return redirect()->route('users.index')
                        ->with('success','User created successfully');
    }

    /**
     * Display the specified resource.
     *
     * @param  int  $id
     * @return \Illuminate\Http\Response
     */
    public function show($id)
    {
        $user = User::find($id);
        return view('users.show',compact('user'));
    }

    /**
     * Show the form for editing the specified resource.
     *
     * @param  int  $id
     * @return \Illuminate\Http\Response
     */
    public function edit($id)
    {
        $user = User::find($id);
        $roles = Role::pluck('name','name')->all();
        $userRole = $user->roles->pluck('name','name')->all();

        return view('users.edit',compact('user','roles','userRole'));
    }

    /**
     * Update the specified resource in storage.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  int  $id
     * @return \Illuminate\Http\Response
     */
    public function update(Request $request, $id)
    {
        $this->validate($request, [
            'name' => 'required',
            'email' => 'required|email|unique:users,email,'.$id,
            'password' => 'same:confirm-password',
            'roles' => 'required'
        ]);

        $input = $request->all();
        if(!empty($input['password'])){ 
            $input['password'] = Hash::make($input['password']);
        }else{
            $input = array_except($input,array('password'));    
        }

        $user = User::find($id);
        $user->update($input);
        DB::table('model_has_roles')->where('model_id',$id)->delete();

        $user->assignRole($request->input('roles'));

        return redirect()->route('users.index')
                        ->with('success','User updated successfully');
    }

    /**
     * Remove the specified resource from storage.
     *
     * @param  int  $id
     * @return \Illuminate\Http\Response
     */
    public function destroy($id)
    {
        User::find($id)->delete();
        return redirect()->route('users.index')
                        ->with('success','User deleted successfully');
    }
}

app/Http/Controllers/ProductController.php

<?php

namespace App\Http\Controllers;

use App\Product;
use Illuminate\Http\Request;

class ProductController extends Controller
{ 
    /**
     * Display a listing of the resource.
     *
     * @return \Illuminate\Http\Response
     */
    function __construct()
    {
         $this->middleware('permission:product-list|product-create|product-edit|product-delete', ['only' => ['index','show']]);
         $this->middleware('permission:product-create', ['only' => ['create','store']]);
         $this->middleware('permission:product-edit', ['only' => ['edit','update']]);
         $this->middleware('permission:product-delete', ['only' => ['destroy']]);
    }
    /**
     * Display a listing of the resource.
     *
     * @return \Illuminate\Http\Response
     */
    public function index()
    {
        $products = Product::latest()->paginate(5);
        return view('products.index',compact('products'))
            ->with('i', (request()->input('page', 1) - 1) * 5);
    }

    /**
     * Show the form for creating a new resource.
     *
     * @return \Illuminate\Http\Response
     */
    public function create()
    {
        return view('products.create');
    }

    /**
     * Store a newly created resource in storage.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return \Illuminate\Http\Response
     */
    public function store(Request $request)
    {
        request()->validate([
            'name' => 'required',
            'detail' => 'required',
        ]);

        Product::create($request->all());

        return redirect()->route('products.index')
                        ->with('success','Product created successfully.');
    }

    /**
     * Display the specified resource.
     *
     * @param  \App\Product  $product
     * @return \Illuminate\Http\Response
     */
    public function show(Product $product)
    {
        return view('products.show',compact('product'));
    }

    /**
     * Show the form for editing the specified resource.
     *
     * @param  \App\Product  $product
     * @return \Illuminate\Http\Response
     */
    public function edit(Product $product)
    {
        return view('products.edit',compact('product'));
    }

    /**
     * Update the specified resource in storage.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \App\Product  $product
     * @return \Illuminate\Http\Response
     */
    public function update(Request $request, Product $product)
    {
         request()->validate([
            'name' => 'required',
            'detail' => 'required',
        ]);

        $product->update($request->all());

        return redirect()->route('products.index')
                        ->with('success','Product updated successfully');
    }

    /**
     * Remove the specified resource from storage.
     *
     * @param  \App\Product  $product
     * @return \Illuminate\Http\Response
     */
    public function destroy(Product $product)
    {
        $product->delete();

        return redirect()->route('products.index')
                        ->with('success','Product deleted successfully');
    }
}

app/Http/Controllers/RoleController.php

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\Http\Controllers\Controller;
use Spatie\Permission\Models\Role;
use Spatie\Permission\Models\Permission;
use DB;

class RoleController extends Controller
{
    /**
     * Display a listing of the resource.
     *
     * @return \Illuminate\Http\Response
     */
    function __construct()
    {
         $this->middleware('permission:role-list|role-create|role-edit|role-delete', ['only' => ['index','store']]);
         $this->middleware('permission:role-create', ['only' => ['create','store']]);
         $this->middleware('permission:role-edit', ['only' => ['edit','update']]);
         $this->middleware('permission:role-delete', ['only' => ['destroy']]);
    }

    /**
     * Display a listing of the resource.
     *
     * @return \Illuminate\Http\Response
     */
    public function index(Request $request)
    {
        $roles = Role::orderBy('id','DESC')->paginate(5);
        return view('roles.index',compact('roles'))
            ->with('i', ($request->input('page', 1) - 1) * 5);
    }

    /**
     * Show the form for creating a new resource.
     *
     * @return \Illuminate\Http\Response
     */
    public function create()
    {
        $permission = Permission::get();
        return view('roles.create',compact('permission'));
    }

    /**
     * Store a newly created resource in storage.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return \Illuminate\Http\Response
     */
    public function store(Request $request)
    {
        $this->validate($request, [
            'name' => 'required|unique:roles,name',
            'permission' => 'required',
        ]);

        $role = Role::create(['name' => $request->input('name')]);
        $role->syncPermissions($request->input('permission'));

        return redirect()->route('roles.index')
                        ->with('success','Role created successfully');
    }
    /**
     * Display the specified resource.
     *
     * @param  int  $id
     * @return \Illuminate\Http\Response
     */
    public function show($id)
    {
        $role = Role::find($id);
        $rolePermissions = Permission::join("role_has_permissions","role_has_permissions.permission_id","=","permissions.id")
            ->where("role_has_permissions.role_id",$id)
            ->get();

        return view('roles.show',compact('role','rolePermissions'));
    }

    /**
     * Show the form for editing the specified resource.
     *
     * @param  int  $id
     * @return \Illuminate\Http\Response
     */
    public function edit($id)
    {
        $role = Role::find($id);
        $permission = Permission::get();
        $rolePermissions = DB::table("role_has_permissions")->where("role_has_permissions.role_id",$id)
            ->pluck('role_has_permissions.permission_id','role_has_permissions.permission_id')
            ->all();

        return view('roles.edit',compact('role','permission','rolePermissions'));
    }

    /**
     * Update the specified resource in storage.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  int  $id
     * @return \Illuminate\Http\Response
     */
    public function update(Request $request, $id)
    {
        $this->validate($request, [
            'name' => 'required',
            'permission' => 'required',
        ]);

        $role = Role::find($id);
        $role->name = $request->input('name');
        $role->save();

        $role->syncPermissions($request->input('permission'));

        return redirect()->route('roles.index')
                        ->with('success','Role updated successfully');
    }
    /**
     * Remove the specified resource from storage.
     *
     * @param  int  $id
     * @return \Illuminate\Http\Response
     */
    public function destroy($id)
    {
        DB::table("roles")->where('id',$id)->delete();
        return redirect()->route('roles.index')
                        ->with('success','Role deleted successfully');
    }
}

Step 9: Add Blade Files

This is last step we have to add numbers view for layouts, users module, roles module, products modules and errors page, so create number of view like as bellow:

resources/views/layouts/app.blade.php

<html lang="{{ app()->getLocale() }}">
<head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- CSRF Token -->
    <meta name="csrf-token" content="{{ csrf_token() }}">
    <title>{{ config('app.name', 'Laravel 5.8 User Roles and Permissions Tutorial') }}</title>
    <!-- Scripts -->
    <script src="{{ asset('js/app.js') }}" defer></script>
    <!-- Fonts -->
    <link rel="dns-prefetch" href="https://fonts.gstatic.com">
    <link href="https://fonts.googleapis.com/css?family=Raleway:300,400,600" rel="stylesheet" type="text/css">
    <!-- Styles -->
    <link href="{{ asset('css/app.css') }}" rel="stylesheet">
</head>
<body>
    <div id="app">
        <nav class="navbar navbar-expand-md navbar-light navbar-laravel">
            <div class="container">
                <a class="navbar-brand" href="{{ url('/') }}">
                    Laravel 5.8 User Roles and Permissions - ItSolutionStuff.com
                </a>
                <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
                    <span class="navbar-toggler-icon"></span>
                </button>

                <div class="collapse navbar-collapse" id="navbarSupportedContent">
                    <!-- Left Side Of Navbar -->
                    <ul class="navbar-nav mr-auto"></ul>

                    <!-- Right Side Of Navbar -->
                    <ul class="navbar-nav ml-auto">
                        <!-- Authentication Links -->
                        @guest
                            <li><a class="nav-link" href="{{ route('login') }}">{{ __('Login') }}</a></li>
                            <li><a class="nav-link" href="{{ route('register') }}">{{ __('Register') }}</a></li>
                        @else
                            <li><a class="nav-link" href="{{ route('users.index') }}">Manage Users</a></li>
                            <li><a class="nav-link" href="{{ route('roles.index') }}">Manage Role</a></li>
                            <li><a class="nav-link" href="{{ route('products.index') }}">Manage Product</a></li>
                            <li class="nav-item dropdown">
                                <a id="navbarDropdown" class="nav-link dropdown-toggle" href="#" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false" v-pre>
                                    {{ Auth::user()->name }} <span class="caret"></span>
                                </a>

                                <div class="dropdown-menu" aria-labelledby="navbarDropdown">
                                    <a class="dropdown-item" href="{{ route('logout') }}"
                                       onclick="event.preventDefault();
                                                     document.getElementById('logout-form').submit();">
                                        {{ __('Logout') }}
                                    </a>

                                    <form id="logout-form" action="{{ route('logout') }}" method="POST" style="display: none;">
                                        @csrf
                                    </form>
                                </div>
                            </li>
                        @endguest
                    </ul>
                </div>
            </div>
        </nav>

        <main class="py-4">
            <div class="container">
            @yield('content')
            </div>
        </main>
    </div>
</body>
</html>

resources/views/users/index.blade.php

@extends('layouts.app')

@section('content')
<div class="row">
    <div class="col-lg-12 margin-tb">
        <div class="pull-left">
            <h2>Users Management</h2>
        </div>
        <div class="pull-right">
            <a class="btn btn-success" href="{{ route('users.create') }}"> Create New User</a>
        </div>
    </div>
</div>

@if ($message = Session::get('success'))
<div class="alert alert-success">
  <p>{{ $message }}</p>
</div>
@endif

<table class="table table-bordered">
 <tr>
   <th>No</th>
   <th>Name</th>
   <th>Email</th>
   <th>Roles</th>
   <th width="280px">Action</th>
 </tr>
 @foreach ($data as $key => $user)
  <tr>
    <td>{{ ++$i }}</td>
    <td>{{ $user->name }}</td>
    <td>{{ $user->email }}</td>
    <td>
      @if(!empty($user->getRoleNames()))
        @foreach($user->getRoleNames() as $v)
           <label class="badge badge-success">{{ $v }}</label>
        @endforeach
      @endif
    </td>
    <td>
       <a class="btn btn-info" href="{{ route('users.show',$user->id) }}">Show</a>
       <a class="btn btn-primary" href="{{ route('users.edit',$user->id) }}">Edit</a>
        {!! Form::open(['method' => 'DELETE','route' => ['users.destroy', $user->id],'style'=>'display:inline']) !!}
            {!! Form::submit('Delete', ['class' => 'btn btn-danger']) !!}
        {!! Form::close() !!}
    </td>
  </tr>
 @endforeach
</table>

{!! $data->render() !!}

<p class="text-center text-primary"><small>Tutorial by ItSolutionStuff.com</small></p>
@endsection

resources/views/users/create.blade.php

@extends('layouts.app')

@section('content')
<div class="row">
    <div class="col-lg-12 margin-tb">
        <div class="pull-left">
            <h2>Create New User</h2>
        </div>
        <div class="pull-right">
            <a class="btn btn-primary" href="{{ route('users.index') }}"> Back</a>
        </div>
    </div>
</div>

@if (count($errors) > 0)
  <div class="alert alert-danger">
    <strong>Whoops!</strong> There were some problems with your input.<br><br>
    <ul>
       @foreach ($errors->all() as $error)
         <li>{{ $error }}</li>
       @endforeach
    </ul>
  </div>
@endif


{!! Form::open(array('route' => 'users.store','method'=>'POST')) !!}
<div class="row">
    <div class="col-xs-12 col-sm-12 col-md-12">
        <div class="form-group">
            <strong>Name:</strong>
            {!! Form::text('name', null, array('placeholder' => 'Name','class' => 'form-control')) !!}
        </div>
    </div>
    <div class="col-xs-12 col-sm-12 col-md-12">
        <div class="form-group">
            <strong>Email:</strong>
            {!! Form::text('email', null, array('placeholder' => 'Email','class' => 'form-control')) !!}
        </div>
    </div>
    <div class="col-xs-12 col-sm-12 col-md-12">
        <div class="form-group">
            <strong>Password:</strong>
            {!! Form::password('password', array('placeholder' => 'Password','class' => 'form-control')) !!}
        </div>
    </div>
    <div class="col-xs-12 col-sm-12 col-md-12">
        <div class="form-group">
            <strong>Confirm Password:</strong>
            {!! Form::password('confirm-password', array('placeholder' => 'Confirm Password','class' => 'form-control')) !!}
        </div>
    </div>
    <div class="col-xs-12 col-sm-12 col-md-12">
        <div class="form-group">
            <strong>Role:</strong>
            {!! Form::select('roles[]', $roles,[], array('class' => 'form-control','multiple')) !!}
        </div>
    </div>
    <div class="col-xs-12 col-sm-12 col-md-12 text-center">
        <button type="submit" class="btn btn-primary">Submit</button>
    </div>
</div>
{!! Form::close() !!}

<p class="text-center text-primary"><small>Tutorial by ItSolutionStuff.com</small></p>
@endsection

resources/views/users/edit.blade.php

@extends('layouts.app')

@section('content')
<div class="row">
    <div class="col-lg-12 margin-tb">
        <div class="pull-left">
            <h2>Edit New User</h2>
        </div>
        <div class="pull-right">
            <a class="btn btn-primary" href="{{ route('users.index') }}"> Back</a>
        </div>
    </div>
</div>

@if (count($errors) > 0)
  <div class="alert alert-danger">
    <strong>Whoops!</strong> There were some problems with your input.<br><br>
    <ul>
       @foreach ($errors->all() as $error)
         <li>{{ $error }}</li>
       @endforeach
    </ul>
  </div>
@endif

{!! Form::model($user, ['method' => 'PATCH','route' => ['users.update', $user->id]]) !!}
<div class="row">
    <div class="col-xs-12 col-sm-12 col-md-12">
        <div class="form-group">
            <strong>Name:</strong>
            {!! Form::text('name', null, array('placeholder' => 'Name','class' => 'form-control')) !!}
        </div>
    </div>
    <div class="col-xs-12 col-sm-12 col-md-12">
        <div class="form-group">
            <strong>Email:</strong>
            {!! Form::text('email', null, array('placeholder' => 'Email','class' => 'form-control')) !!}
        </div>
    </div>
    <div class="col-xs-12 col-sm-12 col-md-12">
        <div class="form-group">
            <strong>Password:</strong>
            {!! Form::password('password', array('placeholder' => 'Password','class' => 'form-control')) !!}
        </div>
    </div>
    <div class="col-xs-12 col-sm-12 col-md-12">
        <div class="form-group">
            <strong>Confirm Password:</strong>
            {!! Form::password('confirm-password', array('placeholder' => 'Confirm Password','class' => 'form-control')) !!}
        </div>
    </div>
    <div class="col-xs-12 col-sm-12 col-md-12">
        <div class="form-group">
            <strong>Role:</strong>
            {!! Form::select('roles[]', $roles,$userRole, array('class' => 'form-control','multiple')) !!}
        </div>
    </div>
    <div class="col-xs-12 col-sm-12 col-md-12 text-center">
        <button type="submit" class="btn btn-primary">Submit</button>
    </div>
</div>
{!! Form::close() !!}

<p class="text-center text-primary"><small>Tutorial by ItSolutionStuff.com</small></p>
@endsection

resources/views/users/show.blade.php

@extends('layouts.app')

@section('content')
<div class="row">
    <div class="col-lg-12 margin-tb">
        <div class="pull-left">
            <h2> Show User</h2>
        </div>
        <div class="pull-right">
            <a class="btn btn-primary" href="{{ route('users.index') }}"> Back</a>
        </div>
    </div>
</div>

<div class="row">
    <div class="col-xs-12 col-sm-12 col-md-12">
        <div class="form-group">
            <strong>Name:</strong>
            {{ $user->name }}
        </div>
    </div>
    <div class="col-xs-12 col-sm-12 col-md-12">
        <div class="form-group">
            <strong>Email:</strong>
            {{ $user->email }}
        </div>
    </div>
    <div class="col-xs-12 col-sm-12 col-md-12">
        <div class="form-group">
            <strong>Roles:</strong>
            @if(!empty($user->getRoleNames()))
                @foreach($user->getRoleNames() as $v)
                    <label class="badge badge-success">{{ $v }}</label>
                @endforeach
            @endif
        </div>
    </div>
</div>
@endsection

resources/views/roles/index.blade.php

@extends('layouts.app')

@section('content')
<div class="row">
    <div class="col-lg-12 margin-tb">
        <div class="pull-left">
            <h2>Role Management</h2>
        </div>
        <div class="pull-right">
        @can('role-create')
            <a class="btn btn-success" href="{{ route('roles.create') }}"> Create New Role</a>
            @endcan
        </div>
    </div>
</div>

@if ($message = Session::get('success'))
    <div class="alert alert-success">
        <p>{{ $message }}</p>
    </div>
@endif

<table class="table table-bordered">
  <tr>
     <th>No</th>
     <th>Name</th>
     <th width="280px">Action</th>
  </tr>
    @foreach ($roles as $key => $role)
    <tr>
        <td>{{ ++$i }}</td>
        <td>{{ $role->name }}</td>
        <td>
            <a class="btn btn-info" href="{{ route('roles.show',$role->id) }}">Show</a>
            @can('role-edit')
                <a class="btn btn-primary" href="{{ route('roles.edit',$role->id) }}">Edit</a>
            @endcan
            @can('role-delete')
                {!! Form::open(['method' => 'DELETE','route' => ['roles.destroy', $role->id],'style'=>'display:inline']) !!}
                    {!! Form::submit('Delete', ['class' => 'btn btn-danger']) !!}
                {!! Form::close() !!}
            @endcan
        </td>
    </tr>
    @endforeach
</table>

{!! $roles->render() !!}

<p class="text-center text-primary"><small>Tutorial by ItSolutionStuff.com</small></p>
@endsection

resources/views/roles/create.blade.php

@extends('layouts.app')

@section('content')
<div class="row">
    <div class="col-lg-12 margin-tb">
        <div class="pull-left">
            <h2>Create New Role</h2>
        </div>
        <div class="pull-right">
            <a class="btn btn-primary" href="{{ route('roles.index') }}"> Back</a>
        </div>
    </div>
</div>

@if (count($errors) > 0)
    <div class="alert alert-danger">
        <strong>Whoops!</strong> There were some problems with your input.<br><br>
        <ul>
        @foreach ($errors->all() as $error)
            <li>{{ $error }}</li>
        @endforeach
        </ul>
    </div>
@endif

{!! Form::open(array('route' => 'roles.store','method'=>'POST')) !!}
<div class="row">
    <div class="col-xs-12 col-sm-12 col-md-12">
        <div class="form-group">
            <strong>Name:</strong>
            {!! Form::text('name', null, array('placeholder' => 'Name','class' => 'form-control')) !!}
        </div>
    </div>
    <div class="col-xs-12 col-sm-12 col-md-12">
        <div class="form-group">
            <strong>Permission:</strong>
            <br/>
            @foreach($permission as $value)
                <label>{{ Form::checkbox('permission[]', $value->id, false, array('class' => 'name')) }}
                {{ $value->name }}</label>
            <br/>
            @endforeach
        </div>
    </div>
    <div class="col-xs-12 col-sm-12 col-md-12 text-center">
        <button type="submit" class="btn btn-primary">Submit</button>
    </div>
</div>
{!! Form::close() !!}

<p class="text-center text-primary"><small>Tutorial by ItSolutionStuff.com</small></p>
@endsection

resources/views/roles/edit.blade.php

@extends('layouts.app')

@section('content')
<div class="row">
    <div class="col-lg-12 margin-tb">
        <div class="pull-left">
            <h2>Edit Role</h2>
        </div>
        <div class="pull-right">
            <a class="btn btn-primary" href="{{ route('roles.index') }}"> Back</a>
        </div>
    </div>
</div>

@if (count($errors) > 0)
    <div class="alert alert-danger">
        <strong>Whoops!</strong> There were some problems with your input.<br><br>
        <ul>
        @foreach ($errors->all() as $error)
            <li>{{ $error }}</li>
        @endforeach
        </ul>
    </div>
@endif

{!! Form::model($role, ['method' => 'PATCH','route' => ['roles.update', $role->id]]) !!}
<div class="row">
    <div class="col-xs-12 col-sm-12 col-md-12">
        <div class="form-group">
            <strong>Name:</strong>
            {!! Form::text('name', null, array('placeholder' => 'Name','class' => 'form-control')) !!}
        </div>
    </div>
    <div class="col-xs-12 col-sm-12 col-md-12">
        <div class="form-group">
            <strong>Permission:</strong>
            <br/>
            @foreach($permission as $value)
                <label>{{ Form::checkbox('permission[]', $value->id, in_array($value->id, $rolePermissions) ? true : false, array('class' => 'name')) }}
                {{ $value->name }}</label>
            <br/>
            @endforeach
        </div>
    </div>
    <div class="col-xs-12 col-sm-12 col-md-12 text-center">
        <button type="submit" class="btn btn-primary">Submit</button>
    </div>
</div>
{!! Form::close() !!}

@endsection
<p class="text-center text-primary"><small>Tutorial by ItSolutionStuff.com</small></p>

resources/views/roles/show.blade.php

@extends('layouts.app')

@section('content')
<div class="row">
    <div class="col-lg-12 margin-tb">
        <div class="pull-left">
            <h2> Show Role</h2>
        </div>
        <div class="pull-right">
            <a class="btn btn-primary" href="{{ route('roles.index') }}"> Back</a>
        </div>
    </div>
</div>

<div class="row">
    <div class="col-xs-12 col-sm-12 col-md-12">
        <div class="form-group">
            <strong>Name:</strong>
            {{ $role->name }}
        </div>
    </div>
    <div class="col-xs-12 col-sm-12 col-md-12">
        <div class="form-group">
            <strong>Permissions:</strong>
            @if(!empty($rolePermissions))
                @foreach($rolePermissions as $v)
                    <label class="label label-success">{{ $v->name }},</label>
                @endforeach
            @endif
        </div>
    </div>
</div>
@endsection

resources/views/products/index.blade.php

@extends('layouts.app')

@section('content')
    <div class="row">
        <div class="col-lg-12 margin-tb">
            <div class="pull-left">
                <h2>Products</h2>
            </div>
            <div class="pull-right">
                @can('product-create')
                <a class="btn btn-success" href="{{ route('products.create') }}"> Create New Product</a>
                @endcan
            </div>
        </div>
    </div>

    @if ($message = Session::get('success'))
        <div class="alert alert-success">
            <p>{{ $message }}</p>
        </div>
    @endif

    <table class="table table-bordered">
        <tr>
            <th>No</th>
            <th>Name</th>
            <th>Details</th>
            <th width="280px">Action</th>
        </tr>
	    @foreach ($products as $product)
	    <tr>
	        <td>{{ ++$i }}</td>
	        <td>{{ $product->name }}</td>
	        <td>{{ $product->detail }}</td>
	        <td>
                <form action="{{ route('products.destroy',$product->id) }}" method="POST">
                    <a class="btn btn-info" href="{{ route('products.show',$product->id) }}">Show</a>
                    @can('product-edit')
                    <a class="btn btn-primary" href="{{ route('products.edit',$product->id) }}">Edit</a>
                    @endcan

                    @csrf
                    @method('DELETE')
                    @can('product-delete')
                    <button type="submit" class="btn btn-danger">Delete</button>
                    @endcan
                </form>
	        </td>
	    </tr>
	    @endforeach
    </table>

    {!! $products->links() !!}

<p class="text-center text-primary"><small>Tutorial by ItSolutionStuff.com</small></p>
@endsection

resources/views/products/create.blade.php

@extends('layouts.app')

@section('content')
    <div class="row">
        <div class="col-lg-12 margin-tb">
            <div class="pull-left">
                <h2>Add New Product</h2>
            </div>
            <div class="pull-right">
                <a class="btn btn-primary" href="{{ route('products.index') }}"> Back</a>
            </div>
        </div>
    </div>

    @if ($errors->any())
        <div class="alert alert-danger">
            <strong>Whoops!</strong> There were some problems with your input.<br><br>
            <ul>
                @foreach ($errors->all() as $error)
                    <li>{{ $error }}</li>
                @endforeach
            </ul>
        </div>
    @endif

    <form action="{{ route('products.store') }}" method="POST">
    	@csrf

         <div class="row">
		    <div class="col-xs-12 col-sm-12 col-md-12">
		        <div class="form-group">
		            <strong>Name:</strong>
		            <input type="text" name="name" class="form-control" placeholder="Name">
		        </div>
		    </div>
		    <div class="col-xs-12 col-sm-12 col-md-12">
		        <div class="form-group">
		            <strong>Detail:</strong>
		            <textarea class="form-control" style="height:150px" name="detail" placeholder="Detail"></textarea>
		        </div>
		    </div>
		    <div class="col-xs-12 col-sm-12 col-md-12 text-center">
		            <button type="submit" class="btn btn-primary">Submit</button>
		    </div>
		</div>

    </form>

<p class="text-center text-primary"><small>Tutorial by ItSolutionStuff.com</small></p>
@endsection

resources/views/products/edit.blade.php

@extends('layouts.app')

@section('content')
    <div class="row">
        <div class="col-lg-12 margin-tb">
            <div class="pull-left">
                <h2>Edit Product</h2>
            </div>
            <div class="pull-right">
                <a class="btn btn-primary" href="{{ route('products.index') }}"> Back</a>
            </div>
        </div>
    </div>

    @if ($errors->any())
        <div class="alert alert-danger">
            <strong>Whoops!</strong> There were some problems with your input.<br><br>
            <ul>
                @foreach ($errors->all() as $error)
                    <li>{{ $error }}</li>
                @endforeach
            </ul>
        </div>
    @endif

    <form action="{{ route('products.update',$product->id) }}" method="POST">
    	@csrf
        @method('PUT')

         <div class="row">
		    <div class="col-xs-12 col-sm-12 col-md-12">
		        <div class="form-group">
		            <strong>Name:</strong>
		            <input type="text" name="name" value="{{ $product->name }}" class="form-control" placeholder="Name">
		        </div>
		    </div>
		    <div class="col-xs-12 col-sm-12 col-md-12">
		        <div class="form-group">
		            <strong>Detail:</strong>
		            <textarea class="form-control" style="height:150px" name="detail" placeholder="Detail">{{ $product->detail }}</textarea>
		        </div>
		    </div>
		    <div class="col-xs-12 col-sm-12 col-md-12 text-center">
		      <button type="submit" class="btn btn-primary">Submit</button>
		    </div>
		</div>

    </form>

<p class="text-center text-primary"><small>Tutorial by ItSolutionStuff.com</small></p>
@endsection

resources/views/products/show.blade.php

@extends('layouts.app')

@section('content')
    <div class="row">
        <div class="col-lg-12 margin-tb">
            <div class="pull-left">
                <h2> Show Product</h2>
            </div>
            <div class="pull-right">
                <a class="btn btn-primary" href="{{ route('products.index') }}"> Back</a>
            </div>
        </div>
    </div>

    <div class="row">
        <div class="col-xs-12 col-sm-12 col-md-12">
            <div class="form-group">
                <strong>Name:</strong>
                {{ $product->name }}
            </div>
        </div>
        <div class="col-xs-12 col-sm-12 col-md-12">
            <div class="form-group">
                <strong>Details:</strong>
                {{ $product->detail }}
            </div>
        </div>
    </div>
@endsection
<p class="text-center text-primary"><small>Tutorial by ItSolutionStuff.com</small></p>

Step 10: Handle Exertion Error

Now, in this step we will handle exertion. if you don't have a permission and try to access that page using browser url then you can give message as like bellow:

add/Exceptions/Handler.php

......
public function render($request, Exception $exception)
{
    if ($exception instanceof \Spatie\Permission\Exceptions\UnauthorizedException) {
        return response()->json(['User have not permission for this page access.']);
    }
 
    return parent::render($request, $exception);
}
....

Step 11: Create Seeder For Permissions and AdminUser

In this step we will create seeder for permissions, Right now we have fixed permission so we create using seeder as listed bellow, but if you can add more permission as you want:

1.role-list

2.role-create

3.role-edit

4.role-delete

5.product-list

6.product-create

7.product-edit

8.product-delete

So, first create seeder using bellow command:

php artisan make:seeder PermissionTableSeeder

And put bellow code in PermissionTableSeeder seeder this way:

database/seeds/PermissionTableSeeder.php

<?php

use Illuminate\Database\Seeder;
use Spatie\Permission\Models\Permission;

class PermissionTableSeeder extends Seeder
{
    /**
     * Run the database seeds.
     *
     * @return void
     */
    public function run()
    {
       $permissions = [
           'role-list',
           'role-create',
           'role-edit',
           'role-delete',
           'product-list',
           'product-create',
           'product-edit',
           'product-delete'
        ];

        foreach ($permissions as $permission) {
             Permission::create(['name' => $permission]);
        }
    }
}

After this we have to run bellow command for run PermissionTableSeeder seeder:

php artisan db:seed --class=PermissionTableSeeder

Now let's create new seeder for creating admin user.

php artisan make:seeder CreateAdminUserSeeder

database/seeds/PermissionTableSeeder.php

<?php
  
use Illuminate\Database\Seeder;
use App\User;
use Spatie\Permission\Models\Role;
use Spatie\Permission\Models\Permission;
  
class CreateAdminUserSeeder extends Seeder
{
    /**
     * Run the database seeds.
     *
     * @return void
     */
    public function run()
    {
        $user = User::create([
        	'name' => 'Hardik Savani', 
        	'email' => '[email protected]',
        	'password' => bcrypt('123456')
        ]);
  
        $role = Role::create(['name' => 'Admin']);
   
        $permissions = Permission::pluck('id','id')->all();
  
        $role->syncPermissions($permissions);
   
        $user->assignRole([$role->id]);
    }
}
php artisan db:seed --class=CreateAdminUserSeeder

Now we are ready to to run full example of ACL. so let's run our example so run bellow command for quick run:

php artisan serve

Access By

http://localhost:8000/

Now you can login with following credential:

Email: [email protected]
Password: 123456

You can see bellow screenshots:

You can download code from GitHub

Creating a Modal Dialog in Angular 8 with TypeScript

Creating a Modal Dialog in Angular 8 with TypeScript

In this tutorial we'll cover how to implement modal windows (dialog boxes) in Angular 8 with TypeScript. The example is a custom modal without the need for any 3rd party libraries.

There are plenty of plugins and libraries out there that include modal windows, in the past I used them myself when I needed to add a modal to a new project. The main issue I have with 3rd party plugins is that they usually contain a lot of features I don't need which adds unnecessary bloat to my Angular app, so a while ago I took some time to implement a custom modal window to see how difficult it would be and also to remove the magic & mystery I had in my mind about exactly how modals work.

When I finished I was pleasantly surprised at the relatively small amount of code required to implement a custom modal window, most of the modal 'magic' is done with a handful of CSS styles (see modal.component.less) while Angular / TypeScript is just used for showing and hiding the modal windows.

Running the Angular 8 Modal Dialog Locally
  1. Install NodeJS and NPM from https://nodejs.org/en/download/.
  2. Download or clone the project source code from https://github.com/cornflourblue/angular-8-custom-modal
  3. Install all required npm packages by running npm install from the command line in the project root folder (where the package.json is located).
  4. Start the application by running npm start from the command line in the project root folder.

NOTE: You can also run the app directly using the Angular CLI command ng serve --open. To do this first install the Angular CLI globally on your system with the command npm install -g @angular/cli.

Adding Custom Modals to Your Angular 8 App

To add modals to your Angular 8 application you'll need to copy the /src/app/_modal folder and contents from the example project, the folder contains the modal module and associated files, including:

  • modal.model.less - LESS/CSS styles for displaying modal dialogs, this is where the modal "magic" happens.
  • modal.component.html - modal component template that contains the wrapper html for displaying modal dialogs.
  • modal.component.ts - modal component with the logic for displaying modal dialogs.
  • modal.module.ts - modal module that encapsulates the modal component so it can be imported by the app module.
  • modal.service.ts - modal service that can be used by any angular component to open and close modal dialogs.
  • index.ts - barrel file that re-exports the modal module and service so they can be imported using only the folder path instead of the full path to each file, and also enables importing from multiple files with a single import.

Import the Modal Module into your App Module

To make the modal component available to your Angular 8 application you need to add the ModalModule to the imports array of your App Module (app.module.ts). See the app module from the example app below, the modal module is imported on line 5 and added to the imports array of the app module on line 16.

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { FormsModule } from '@angular/forms';

import { ModalModule } from './_modal';
import { appRoutingModule } from './app.routing';

import { AppComponent } from './app.component';
import { HomeComponent } from './home';
import { TestPageComponent } from './test-page';

@NgModule({
    imports: [
        BrowserModule,
        FormsModule,
        ModalModule,
        appRoutingModule
    ],
    declarations: [
        AppComponent,
        HomeComponent,
        TestPageComponent
    ],
    bootstrap: [AppComponent]
})

export class AppModule { }

Add the tag to pages where you want to display modals

To add a modal dialog to any page simply add the <jw-modal id="[insert unique id]"></jw-modal> tag along with the content for the modal. You can put any content you like inside the <jw-modal> element. You can also update the modal LESS/CSS if you want to change the styles of the modals, e.g to make them smaller or add CSS animation transitions.

IMPORTANT: A unique id is required for each modal on a page, it can be any string e.g. 'custom-modal-1'. The id string is used by the modal service to keep track of each active modal in the angular app, so the service knows which modal to open/close based on the id passed to the modalService.open() and modalService.close() methods e.g. modalService.open('custom-modal-1').

Here is the home component template from the example app (/src/app/home/home.component.html) that contains two modals, each is opened by a button click, and the first modal contains an input text field that allows you to edit the bodyText displayed in the template.

<div>
    <h1>Home</h1>
    <p>{{bodyText}}</p>
    <button (click)="openModal('custom-modal-1')">Open Modal 1</button>
    <button (click)="openModal('custom-modal-2')">Open Modal 2</button>
</div>

<jw-modal id="custom-modal-1">
    <h1>A Custom Modal!</h1>
    <p>Home page text: <input type="text" [(ngModel)]="bodyText" /></p>
    <button (click)="closeModal('custom-modal-1');">Close</button>
</jw-modal>

<jw-modal id="custom-modal-2">
    <h1 style="height:1000px">A Tall Custom Modal!</h1>
    <button (click)="closeModal('custom-modal-2');">Close</button>
</jw-modal>	

Opening & Closing Angular 8 Modal Dialogs

To open a modal call the modalService.open() method with the id of the modal you want to open, e.g. modalService.open('custom-modal-1'). To close a modal call the modalService.close() method with the id of the modal you want to close, e.g. modalService.close('custom-modal-1').

By default modals are closed on background click, to disable this remove the chunk of code in the modal component (/src/app/_modal/modal.component.ts) located directly below the comment // close modal on background click.

Here is the home component from the example app (/src/app/home/home.component.ts), it contains methods for opening and closing modals (openModal() and closeModal()) that call the corresponding methods of the modal service.

import { Component, OnInit } from '@angular/core';

import { ModalService } from '../_modal';

@Component({ templateUrl: 'home.component.html' })
export class HomeComponent implements OnInit {
    bodyText: string;

    constructor(private modalService: ModalService) { }

    ngOnInit() {
        this.bodyText = 'This text can be updated in modal 1';
    }

    openModal(id: string) {
        this.modalService.open(id);
    }

    closeModal(id: string) {
        this.modalService.close(id);
    }
}	
Breakdown of the Angular 8 Custom Modal Code

Below is a breakdown of the pieces of code used to implement custom modal dialogs in Angular 8 & TypeScript, you don't need to know the details of how it all works to use the modals in your project, it's only if you're interested in the nuts and bolts or if you want to modify the underlying code or behaviour.

LESS/CSS Styles for Angular 8 Modal Dialogs

These are the styles applied to the custom modal dialogs in this example, they could also be used in non-angular projects as it's just pure LESS/CSS.

I prefixed the modal element and classes with jw- to prevent conflicts with 3rd party css libraries such as Bootstrap.

/* MODAL STYLES
-------------------------------*/
jw-modal {
    /* modals are hidden by default */
    display: none;

    .jw-modal {
        /* modal container fixed across whole screen */
        position: fixed;
        top: 0;
        right: 0;
        bottom: 0;
        left: 0;

        /* z-index must be higher than .jw-modal-background */
        z-index: 1000;
        
        /* enables scrolling for tall modals */
        overflow: auto;

        .jw-modal-body {
            padding: 20px;
            background: #fff;

            /* margin exposes part of the modal background */
            margin: 40px;
        }
    }

    .jw-modal-background {
        /* modal background fixed across whole screen */
        position: fixed;
        top: 0;
        right: 0;
        bottom: 0;
        left: 0;

        /* semi-transparent black  */
        background-color: #000;
        opacity: 0.75;
        
        /* z-index must be below .jw-modal and above everything else  */
        z-index: 900;
    }
}

body.jw-modal-open {
    /* body overflow is hidden to hide main scrollbar when modal window is open */
    overflow: hidden;
}	
Angular 8 Modal Service

The Angular 8 modal service manages the communication that's required between page components and modal components. It maintains a list of available modals on the page and exposes methods for interacting with those modals.

import { Injectable } from '@angular/core';

@Injectable({ providedIn: 'root' })
export class ModalService {
    private modals: any[] = [];

    add(modal: any) {
        // add modal to array of active modals
        this.modals.push(modal);
    }

    remove(id: string) {
        // remove modal from array of active modals
        this.modals = this.modals.filter(x => x.id !== id);
    }

    open(id: string) {
        // open modal specified by id
        const modal = this.modals.find(x => x.id === id);
        modal.open();
    }

    close(id: string) {
        // close modal specified by id
        const modal = this.modals.find(x => x.id === id);
        modal.close();
    }
}	
Angular 8 Modal Component

The custom modal component is used to add modal windows anywhere in your angular application by using the <jw-modal> tag. Each modal instance adds itself to the modal service when it loads by calling modalService.add(this) from the ngOnInit Angular lifecycle method, and removes itself from the modal service when it is destroyed by calling modalService.remove(this.id) from the ngOnDestroy Angular lifecycle method.

import { Component, ViewEncapsulation, ElementRef, Input, OnInit, OnDestroy } from '@angular/core';

import { ModalService } from './modal.service';

@Component({ 
    selector: 'jw-modal', 
    templateUrl: 'modal.component.html', 
    styleUrls: ['modal.component.less'],
    encapsulation: ViewEncapsulation.None
})
export class ModalComponent implements OnInit, OnDestroy {
    @Input() id: string;
    private element: any;

    constructor(private modalService: ModalService, private el: ElementRef) {
        this.element = el.nativeElement;
    }

    ngOnInit(): void {
        // ensure id attribute exists
        if (!this.id) {
            console.error('modal must have an id');
            return;
        }

        // move element to bottom of page (just before </body>) so it can be displayed above everything else
        document.body.appendChild(this.element);

        // close modal on background click
        this.element.addEventListener('click', el => {
            if (el.target.className === 'jw-modal') {
                this.close();
            }
        });

        // add self (this modal instance) to the modal service so it's accessible from controllers
        this.modalService.add(this);
    }

    // remove self from modal service when component is destroyed
    ngOnDestroy(): void {
        this.modalService.remove(this.id);
        this.element.remove();
    }

    // open modal
    open(): void {
        this.element.style.display = 'block';
        document.body.classList.add('jw-modal-open');
    }

    // close modal
    close(): void {
        this.element.style.display = 'none';
        document.body.classList.remove('jw-modal-open');
    }
}	
Angular 8 Modal Component Template

The modal component template contains just a couple of wrapper divs for the modal content and a div for the modal background. The <ng-content> element is replaced by Angular with the contents you set inside the <jw-modal> element, this is called Angular content projection.

<div class="jw-modal">
    <div class="jw-modal-body">
        <ng-content></ng-content>
    </div>
</div>
<div class="jw-modal-background"></div>	

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Further reading about AngularJS

Angular 8 (formerly Angular 2) - The Complete Guide

Angular & NodeJS - The MEAN Stack Guide

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The Web Developer Bootcamp

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MEAN Stack Angular 8 CRUD Web Application

Angular 8 Tutorial - User Registration and Login Example

How to build a CRUD Web App with Angular 8.0

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Angular 8 Material Design Tutorial & Example