Create a fully dynamic Tab Component In Angular

A Tab component is an essential part of every web application. Even said so, there are too few open-sourced libraries, that provide it.

Angular Material provides a really flexible and powerful Tab component, but it shifts with a material theme, extra dependencies, and material guidelines.

Creating a Tab component is like a parabola curve. At first, it looks complex, after creating some basic functionalities, it looks much simpler, but after trying to add dynamic functionality, it becomes a complex one again.

#angular-material #programming #javascript #web-development #angular

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Install Angular - Angular Environment Setup Process

Angular is a TypeScript based framework that works in synchronization with HTML, CSS, and JavaScript. To work with angular, domain knowledge of these 3 is required.

1. Installing Node.js and npm
2. Installing Angular CLI
3. Creating workspace
4. Deploying your First App

In this article, you will get to know about the Angular Environment setup process. After reading this article, you will be able to install, setup, create, and launch your own application in Angular. So let’s start!!!

Install Angular in Easy Steps

For Installing Angular on your Machine, there are 2 prerequisites:

• Node.js
• npm Package Manager

Node.js

First you need to have Node.js installed as Angular require current, active LTS or maintenance LTS version of Node.js

Download and Install Node.js version suitable for your machine’s operating system.

Npm Package Manager

Angular, Angular CLI and Angular applications are dependent on npm packages. By installing Node.js, you have automatically installed the npm Package manager which will be the base for installing angular in your system. To check the presence of npm client and Angular version check of npm client, run this command:

1. npm -v

Installing Angular CLI

• Open Terminal/Command Prompt
• To install Angular CLI, run the below command:

1. npm install -g @angular/cli

· After executing the command, Angular CLI will get installed within some time. You can check it using the following command

1. ng --version

Workspace Creation

Now as your Angular CLI is installed, you need to create a workspace to work upon your application. Methods for it are:

• Using CLI
• Using Visual Studio Code

1. Using CLI

To create a workspace:

• Navigate to the desired directory where you want to create your workspace using cd command in the Terminal/Command prompt
• Then in the directory write this command on your terminal and provide the name of the app which you want to create. In my case I have mentioned DataFlair:

1. Ng new YourAppName

• After running this command, it will prompt you to select from various options about the CSS and other functionalities.

• To leave everything to default, simply press the Enter or the Return key.

#angular tutorials #angular cli install #angular environment setup #angular version check #download angular #install angular #install angular cli

Create a fully dynamic Tab Component In Angular

A Tab component is an essential part of every web application. Even said so, there are too few open-sourced libraries, that provide it.

Angular Material provides a really flexible and powerful Tab component, but it shifts with a material theme, extra dependencies, and material guidelines.

Creating a Tab component is like a parabola curve. At first, it looks complex, after creating some basic functionalities, it looks much simpler, but after trying to add dynamic functionality, it becomes a complex one again.

#angular-material #programming #javascript #web-development #angular

Agnostic components in Angular

When you’re building a reusable components library, API is very important. On one hand, you want a tidy, reliable solution, on the other — you need to take care of lots of specific use cases. Learn how to make components that work with everything and look like anything!

When you’re building a reusable components library, API is very important. On one hand, you want a tidy, reliable solution, on the other — you need to take care of lots of specific use cases. And it’s not just about working with diverse data. Your components must be flexible visually. Besides, it has to be easy to update and deliver across projects.

These components must be customizable like no other. And it shouldn’t be hard to do — they will be used by senior and junior developers alike. Also, since one of the reasons to make such a library is to reduce code duplication, configuration must not turn into a copy-paste exercise.

Data-agnostic components#

Say you’re making a drop-down menu button. What would be its API? Surely it would need an array of items for the menu. Probably, the first run would be an interface like the following:

interface MenuItem {
    readonly text: string;
    readonly onClick(): void;
}
<>

Fairly quickly, you’d add an option to disable an item. Then designers would come up with a menu with icons. Then they will draw them on the other side for the fellow project. The interface keeps growing, taking more and more cases into account. Great variety of flags turn your component into the United Nations assembly.

Looking familiar?

Generics to the rescue. If you build your component to not care about the data model at all — this problem seizes to exist. Instead of calling item.onClick it could emit clicked item. What to do with it is up to the library users. They are free to call item.onClick or organize their model differently.

In the case of disabled state, a component would use a handler. It’s a function that takes generic item as an argument and returns whether it is disabled or not. Handling different visual options would be explored later.

---

For a ComboBox, you could come up with an interface with string for display value and a property with the real value behind it. This seems reasonable. After all, when user types into ComboBox, options must be narrowed down by the string input.

interface ComboBoxItem {
    readonly text: string;
    readonly value: any;
}
<>

You would soon uncover limitations of this approach once design pops up where string is not enough. Besides, form contains a wrapper instead of the real value and filtering is not always limited to string representation. You could filter by phone number contacts that show names. And each new component like that brings new interface even if the underlying model is the same.

Here you can also use generics and provide a stringify handler to the component: (item: T) => string. A simple String(item) would work by default. This way, you can even use classes for options by defining toString method. As mentioned earlier, string is not always enough to filter. It’s another good case for handlers — we could pass a matching function to ComboBox. It would take user input and item as arguments and return true if item fits.

Another example where interface is often used — unique id. You might get your value in one request and options later in another. Then you will have a copy of the selected item in the array, not the same reference. Instead of an id property, you could have an identity matching function. It would take two items as arguments with the default value of simple triple _=_ comparison.

Many components, such as tabs, radio buttons, variety of lists don’t need to be aware of the data model they work with. Abstraction over it allows to create extendable code not tied to concrete realization. This means there will be no breaking changes with added features. Users will not have to adapt their data and components fit together like Lego blocks.

The same options component could go in context menu, Select, MultiSelect. Atomic components effortlessly make up bigger structures. However, generic data must be displayed somehow. Lists could have avatars, different colors, unread messages counters and so on.

Example drop-down with custom design

To make this work, we need to approach presentation in the same manner as we took on generic data.

#angular #angular-templates #angular-dynamic-components #typescript #api

Create a Component Harness For Your Tests With Angular CDK

Learn how to create and consume a custom component harness using Angular CDK. With a step-by-step case study, we run it in unit tests and end-to-end tests.

Updated for Angular CDK and Angular Material version 9.2.

A component harness is a testing API around an Angular directive or component. Component harnesses can be shared between unit tests, integration tests, and end-to-end tests. They result in less brittle tests as implementation details are hidden from test suites.

#angular #angular-cdk #component-harnesses #testing #angular-material

Basics of Angular: Part-1

What is Angular? What it does? How we implement it in a project? So, here are some basics of angular to let you learn more about angular.

Angular is a Typescript-based open-source front-end web application platform. The Angular Team at Google and a community of individuals and corporations lead it. Angular lets you extend HTML’s syntax to express your apps’ components clearly. The angular resolves challenges while developing a single page and cross-platform applications. So, here the meaning of the single-page applications in angular is that the index.html file serves the app. And, the index.html file links other files to it.

We build angular applications with basic concepts which are NgModules. It provides a compilation context for components. At the beginning of an angular project, the command-line interface provides a built-in component which is the root component. But, NgModule can add a number of additional components. These can be created through a template or loaded from a router. This is what a compilation context about.

What is a Component in Angular?

Components are key features in Angular. It controls a patch of the screen called a view. A couple of components that we create on our own helps to build a whole application. In the end, the root component or the app component holds our entire application. The component has its business logic that it does to support the view inside the class. The class interacts with the view through an API of properties and methods. All the components added by us in the application are not linked to the index.html. But, they link to the app.component.html through the selectors. A component can be a component and not only a typescript class by adding a decorator @Component. Then, for further access, a class can import it. The decorator contains some metadata like selector, template, and style. Here’s an example of how a component decorator looks like:

@Component({
    selector: 'app-root',
    templateUrl: 'app.component.html',
    styleUrls: ['app.component.scss']
})

Role of App Module

Modules are the package of functionalities of our app. It gives Angular the information about which features does my app has and what feature it uses. It is an empty Typescript class, but we transform it by adding a decorator @NgModule. So, we have four properties that we set up on the object pass to @NgModule. The four properties are declarations, imports, providers, and bootstrap. All the built-in new components add up to the declarations array in @NgModule.

@NgModule({
declarations: [
  AppComponent,
],
imports: [
  BrowserModule,
  HttpClientModule,
  AppRoutingModule,
  FormsModule
],
bootstrap: [AppComponent]
})

What is Data Binding?

Data Binding is the communication between the Typescript code of the component and the template. So, we have different kinds of data binding given below:

• When there is a requirement to output data from our Typescript code in the HTML template. String interpolation handles this purpose like {{data}} in HTML file. Property Binding is also used for this purpose like [property] = “data”.
• When we want to trigger any event like clicking a button. Event Binding works while we react to user events like (event) = “expression”.
• When we can react to user events and output something at the same time. Two-way Binding is used like [(ngModel)] = “data”.

#angular #javascript #tech blogs #user interface (ui) #angular #angular fundamentals #angular tutorial #basics of angular