NPM vs. NPX

NPM vs. NPX

A quick explanation of the difference between npm and npx. Are there any benefits of using npx instead of npm? I know you were trying to find the answer for the above questions and at the end, you landed up on this page. I will try to answer these questions for you. And at the end of the article, I am sure that you will get the answer to your questions. I hope you will find this post useful. 

Introduction

We all are using npm as our package manager. It is easy, right? But with the version [email protected], when you install the npm, it installs a new package called npx. Have you ever thought about what it is? And why it is needed? Are there any benefits of using npx instead of npm? I know you were trying to find the answer for the above questions and at the end, you landed up on this page. I will try to answer these questions for you. And at the end of the article, I am sure that you will get the answer to your questions. I hope you will find this post useful.

What we are going to do

We will be creating two applications and installing the mocha package in both applications so that we can run some tests.

  1. mocha-example-npm
  2. mocha-example-npx

npm-npx

Coding with mocha-example-npm application

Let’s try to create a new folder named mocha-example-npm and open it in my favorite code editor, which is vscode. Once you open the folder, you can install mocha by running this command.

  1. npm install mocha
    Let’s create a folder called test.

  2. mkdir test
    Let’s create a file called test.js.

    code test/test.js

And paste the below sample test in it.

var assert = require('assert');  
describe('Array', function() {  
    describe('#indexOf()', function() {  
        it('should return -1 when the value is not present', function() {  
            assert.equal([1, 2, 3].indexOf(4), -1);  
        });  
    });  
});  

By seeing the code, you might have already found that the test will pass the indexOf (4) as -1. Now how do we check this? So to run the test we need to run mocha right? Let’s do it.

If you just type mocha in the terminal, you will get an error as below.

  1. mocha - The term 'mocha' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again.
At line:1 char:1  
+ mocha  
+ ~~~~~  
+ CategoryInfo : ObjectNotFound: (mocha:String)[], CommandNotFoundException  
+ FullyQualifiedErrorId : CommandNotFoundException  

It is saying that mocha is not a recognized command. To fix this you have three options below.

  • Install mocha globally, so that the command will be recognized globally
[email protected] C:\Program Files(x86)\nodejs\node_modules\npm  
PS F:\SibeeshPassion\Articles\NPMvsNPX\npm\mocha-example-npm> npm i mocha -g  
C:\Users\Sibeesh\AppData\Roaming\npm\mocha -> C:\Users\Sibeesh\AppData\Roaming\npm\node_modules\mocha\bin\mocha  
C:\Users\Sibeesh\AppData\Roaming\npm\_mocha -> C:\Users\Sibeesh\AppData\Roaming\npm\node_modules\mocha\bin\_mocha  
+ [email protected]  
added 24 packages from 436 contributors in 3.458s  
PS F:\SibeeshPassion\Articles\NPMvsNPX\npm\mocha-example-npm> npm list -g mocha  
C:\Users\Sibeesh\AppData\Roaming\npm  
`-- [email protected]  
PS F:\SibeeshPassion\Articles\NPMvsNPX\npm\mocha-example-npm> mocha  
Array  
#indexOf()  
√ should return -1 when the value is not present  
1passing(14ms)  
PS F:\SibeeshPassion\Articles\NPMvsNPX\npm\mocha-example-npm>  
  • Use the path to mocha from node_modules

    ./node_modules/mocha/bin/mocha

  • Configure test in your package.json file as follows.

"scripts":{  
   "test":"mocha"  
}  
So that you can run _npm test_ command, and it will take the mocha files from your node_modules folder.

Coding with mocha-example-npx application

So, we have understood the problem we have using npm and we have three solutions to fix it. Now, let’s try using the npx instead of npm. Let’s open the folder and run npx mocha. The result is a warning as it is trying to find the folder test in the solution and then the tests.

  1. npx: installed 24 in 6.203s
  2. Warning: Could not find any test files matching pattern: test
  3. No test files found

Let’s create a test folder, test.js file and write a test in it.

PS F:\SibeeshPassion\Articles\NPMvsNPX\npx\mocha-example-npx> mkdir test  
Directory: F:\SibeeshPassion\Articles\NPMvsNPX\npx\mocha-example-npx  
Mode LastWriteTime Length Name  
---- ------------- ------ ----  
d----- 20-10-201806:26 PM test  
PS F:\SibeeshPassion\Articles\NPMvsNPX\npx\mocha-example-npx> code test/test.js  
PS F:\SibeeshPassion\Articles\NPMvsNPX\npx\mocha-example-npx>  

Let’s run the command npx mocha now, and you will get the output as below.

PS F:\SibeeshPassion\Articles\NPMvsNPX\npx\mocha-example-npx> npx mocha  
npx: installed 24 in 4.142s  
Array  
#indexOf()  
√ should return -1 when the value is not present  
1passing(12ms)  
PS F:\SibeeshPassion\Articles\NPMvsNPX\npx\mocha-example-npx> 

As you can see that our tests are passed. But are you seeing any node_modules folder or any packages are being added to your solution?

What is npx?

Now, let’s just summarize what npx is. It is an npm package runner. We all know that we are installing the packages to our solution from the location called npm registry and using it. And the npx has been designed in a way that we can directly use the package from the npm registry without even installing it in our solution. You may be thinking why is it needed?

Let me give you an example, as I mentioned in the background section of this article, we can create a simple React application with the help of Create-React-App from FaceBook. And this is used only for creating the application, and once we create the application, we no longer need this. If you use npm, you will have to install this package either globally or locally before you use this, or else you will get an error.

Wouldn't it be good, if we could just use this create-react-app package from the npm registry and create the application in our local machine? And that’s where npx comes in. With the help of npx, we can reduce the size of our node_modules and I strongly believe that this is a huge benefit.

It is smart enough to identify whether the package you are trying to get from the npm registry is already there in your machine, either globally or locally. If the package is available in your machine, it will take it from there.

What if mocha is installed globally or locally and we run the command npx mocha?

Let’s try to install mocha globally and run the command npx mocha. Before that, let’s just make sure that we haven’t installed mocha yet.

PS F:\SibeeshPassion\Articles\NPMvsNPX\npx\mocha-example-npx> npm list mocha  
[email protected] F:\SibeeshPassion\Articles\NPMvsNPX\npx\mocha-example-npx  
`-- (empty)  
PS F:\SibeeshPassion\Articles\NPMvsNPX\npx\mocha-example-npx> npm list -g mocha  
C:\Users\Sibeesh\AppData\Roaming\npm  
`-- (empty)  
PS F:\SibeeshPassion\Articles\NPMvsNPX\npx\mocha-example-npx>  

Now, let’s just install mocha globally

PS F:\SibeeshPassion\Articles\NPMvsNPX\npx\mocha-example-npx> npm i mocha -g  
C:\Users\Sibeesh\AppData\Roaming\npm\mocha -> C:\Users\Sibeesh\AppData\Roaming\npm\node_modules\mocha\bin\mocha  
C:\Users\Sibeesh\AppData\Roaming\npm\_mocha -> C:\Users\Sibeesh\AppData\Roaming\npm\node_modules\mocha\bin\_mocha  
+ [email protected]  
added 24 packages from 436 contributors in 3.033s

Try to run npx mocha again,

PS F:\SibeeshPassion\Articles\NPMvsNPX\npx\mocha-example-npx> npx mocha  
Array  
#indexOf()  
√ should return -1 when the value is not present  
1passing(12ms)  
PS F:\SibeeshPassion\Articles\NPMvsNPX\npx\mocha-example-npx>  

You are not getting any information related to the installation (for example npx: installed 24 in 4.142s).

Conclusion

Thanks a lot for reading. I will come back with another post on the same topic very soon. Did I miss anything that you may think is needed? Did you find this post useful? I hope you liked this article. Please share with me your valuable suggestions and feedback.

Source Code

The source code can be found here.

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Difference between AngularJS, React, Ember, Backbone, and Node.js.

The most common thing between all of them is that they are Single Page Apps. The SPA is a single page where much of the information remains the same and only some piece of data gets modified when you click on other categories/option.

How to Use Express.js, Node.js and MongoDB.js

How to Use Express.js, Node.js and MongoDB.js

In this post, I will show you how to use Express.js, Node.js and MongoDB.js. We will be creating a very simple Node application, that will allow users to input data that they want to store in a MongoDB database. It will also show all items that have been entered into the database.

In this post, I will show you how to use Express.js, Node.js and MongoDB.js. We will be creating a very simple Node application, that will allow users to input data that they want to store in a MongoDB database. It will also show all items that have been entered into the database.

Creating a Node Application

To get started I would recommend creating a new database that will contain our application. For this demo I am creating a directory called node-demo. After creating the directory you will need to change into that directory.

mkdir node-demo
cd node-demo

Once we are in the directory we will need to create an application and we can do this by running the command
npm init

This will ask you a series of questions. Here are the answers I gave to the prompts.

The first step is to create a file that will contain our code for our Node.js server.

touch app.js

In our app.js we are going to add the following code to build a very simple Node.js Application.

var express = require("express");
var app = express();
var port = 3000;
 
app.get("/", (req, res) => {
  res.send("Hello World");
});
 
app.listen(port, () => {
  console.log("Server listening on port " + port);
});

What the code does is require the express.js application. It then creates app by calling express. We define our port to be 3000.

The app.use line will listen to requests from the browser and will return the text “Hello World” back to the browser.

The last line actually starts the server and tells it to listen on port 3000.

Installing Express

Our app.js required the Express.js module. We need to install express in order for this to work properly. Go to your terminal and enter this command.

npm install express --save

This command will install the express module into our package.json. The module is installed as a dependency in our package.json as shown below.

To test our application you can go to the terminal and enter the command

node app.js

Open up a browser and navigate to the url http://localhost:3000

You will see the following in your browser

Creating Website to Save Data to MongoDB Database

Instead of showing the text “Hello World” when people view your application, what we want to do is to show a place for user to save data to the database.

We are going to allow users to enter a first name and a last name that we will be saving in the database.

To do this we will need to create a basic HTML file. In your terminal enter the following command to create an index.html file.

touch index.html

In our index.html file we will be creating an input filed where users can input data that they want to have stored in the database. We will also need a button for users to click on that will add the data to the database.

Here is what our index.html file looks like.

<!DOCTYPE html>
<html>
  <head>
    <title>Intro to Node and MongoDB<title>
  <head>

  <body>
    <h1>Into to Node and MongoDB<&#47;h1>
    <form method="post" action="/addname">
      <label>Enter Your Name<&#47;label><br>
      <input type="text" name="firstName" placeholder="Enter first name..." required>
      <input type="text" name="lastName" placeholder="Enter last name..." required>
      <input type="submit" value="Add Name">
    </form>
  <body>
<html>

If you are familiar with HTML, you will not find anything unusual in our code for our index.html file. We are creating a form where users can input their first name and last name and then click an “Add Name” button.

The form will do a post call to the /addname endpoint. We will be talking about endpoints and post later in this tutorial.

Displaying our Website to Users

We were previously displaying the text “Hello World” to users when they visited our website. Now we want to display our html file that we created. To do this we will need to change the app.use line our our app.js file.

We will be using the sendFile command to show the index.html file. We will need to tell the server exactly where to find the index.html file. We can do that by using a node global call __dirname. The __dirname will provide the current directly where the command was run. We will then append the path to our index.html file.

The app.use lines will need to be changed to
app.use("/", (req, res) => {   res.sendFile(__dirname + "/index.html"); });

Once you have saved your app.js file, we can test it by going to terminal and running node app.js

Open your browser and navigate to “http://localhost:3000”. You will see the following

Connecting to the Database

Now we need to add our database to the application. We will be connecting to a MongoDB database. I am assuming that you already have MongoDB installed and running on your computer.

To connect to the MongoDB database we are going to use a module called Mongoose. We will need to install mongoose module just like we did with express. Go to your terminal and enter the following command.
npm install mongoose --save

This will install the mongoose model and add it as a dependency in our package.json.

Connecting to the Database

Now that we have the mongoose module installed, we need to connect to the database in our app.js file. MongoDB, by default, runs on port 27017. You connect to the database by telling it the location of the database and the name of the database.

In our app.js file after the line for the port and before the app.use line, enter the following two lines to get access to mongoose and to connect to the database. For the database, I am going to use “node-demo”.

var mongoose = require("mongoose"); mongoose.Promise = global.Promise; mongoose.connect("mongodb://localhost:27017/node-demo");

Creating a Database Schema

Once the user enters data in the input field and clicks the add button, we want the contents of the input field to be stored in the database. In order to know the format of the data in the database, we need to have a Schema.

For this tutorial, we will need a very simple Schema that has only two fields. I am going to call the field firstName and lastName. The data stored in both fields will be a String.

After connecting to the database in our app.js we need to define our Schema. Here are the lines you need to add to the app.js.
var nameSchema = new mongoose.Schema({   firstName: String,   lastNameName: String });

Once we have built our Schema, we need to create a model from it. I am going to call my model “DataInput”. Here is the line you will add next to create our mode.
var User = mongoose.model("User", nameSchema);

Creating RESTful API

Now that we have a connection to our database, we need to create the mechanism by which data will be added to the database. This is done through our REST API. We will need to create an endpoint that will be used to send data to our server. Once the server receives this data then it will store the data in the database.

An endpoint is a route that our server will be listening to to get data from the browser. We already have one route that we have created already in the application and that is the route that is listening at the endpoint “/” which is the homepage of our application.

HTTP Verbs in a REST API

The communication between the client(the browser) and the server is done through an HTTP verb. The most common HTTP verbs are
GET, PUT, POST, and DELETE.

The following table explains what each HTTP verb does.

HTTP Verb Operation
GET Read
POST Create
PUT Update
DELETE Delete

As you can see from these verbs, they form the basis of CRUD operations that I talked about previously.

Building a CRUD endpoint

If you remember, the form in our index.html file used a post method to call this endpoint. We will now create this endpoint.

In our previous endpoint we used a “GET” http verb to display the index.html file. We are going to do something very similar but instead of using “GET”, we are going to use “POST”. To get started this is what the framework of our endpoint will look like.

app.post("/addname", (req, res) => {
 
});
Express Middleware

To fill out the contents of our endpoint, we want to store the firstName and lastName entered by the user into the database. The values for firstName and lastName are in the body of the request that we send to the server. We want to capture that data, convert it to JSON and store it into the database.

Express.js version 4 removed all middleware. To parse the data in the body we will need to add middleware into our application to provide this functionality. We will be using the body-parser module. We need to install it, so in your terminal window enter the following command.

npm install body-parser --save

Once it is installed, we will need to require this module and configure it. The configuration will allow us to pass the data for firstName and lastName in the body to the server. It can also convert that data into JSON format. This will be handy because we can take this formatted data and save it directly into our database.

To add the body-parser middleware to our application and configure it, we can add the following lines directly after the line that sets our port.

var bodyParser = require('body-parser');
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));
Saving data to database

Mongoose provides a save function that will take a JSON object and store it in the database. Our body-parser middleware, will convert the user’s input into the JSON format for us.

To save the data into the database, we need to create a new instance of our model that we created early. We will pass into this instance the user’s input. Once we have it then we just need to enter the command “save”.

Mongoose will return a promise on a save to the database. A promise is what is returned when the save to the database completes. This save will either finish successfully or it will fail. A promise provides two methods that will handle both of these scenarios.

If this save to the database was successful it will return to the .then segment of the promise. In this case we want to send text back the user to let them know the data was saved to the database.

If it fails it will return to the .catch segment of the promise. In this case, we want to send text back to the user telling them the data was not saved to the database. It is best practice to also change the statusCode that is returned from the default 200 to a 400. A 400 statusCode signifies that the operation failed.

Now putting all of this together here is what our final endpoint will look like.

app.post("/addname", (req, res) => {
  var myData = new User(req.body);
  myData.save()
    .then(item => {
      res.send("item saved to database");
    })
    .catch(err => {
      res.status(400).send("unable to save to database");
    });
});
Testing our code

Save your code. Go to your terminal and enter the command node app.js to start our server. Open up your browser and navigate to the URL “http://localhost:3000”. You will see our index.html file displayed to you.

Make sure you have mongo running.

Enter your first name and last name in the input fields and then click the “Add Name” button. You should get back text that says the name has been saved to the database like below.

Access to Code

The final version of the code is available in my Github repo. To access the code click here. Thank you for reading !