Express is a minimal and flexible Node.js web application framework that provides a robust set of features for web and mobile applications. Find out more here.

I will create a simple REST API using Express.js. A Representational State Transfer (REST) interface provides a set of operations that can be invoked by a remote client over a network, using the HTTP protocol.

Before we proceed, we must ensure that we have Nodejs installed.

Create directory and navigate to the created directory.

$ mkdir api
$ cd api

We are going to use the ExpressJs nodeJs framework to create our API, so run the code below in your terminal:

npm install express --save
npm install body-parser --save

We need to create an API entry point app.js (or anything you want). Now we will create an app.js file.

var express = require("express");
var bodyParser = require("body-parser");
var routes = require("./routes/routes.js");
var app = express();

app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));

routes(app);

var server = app.listen(3000, function () {
    console.log("app running on port.", server.address().port);
});

The two lines below tell express to accept both JSON and url encoded values

app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));

We defined the port where our server should be running. Also you can define port anything you want.

var server = app.listen(3000, function () {
    console.log("app running on port.", server.address().port);
});

Now we will install faker. Run this command:

npm install faker --save

Now we can edit our routes.js:

var faker = require("faker");

var appRouter = function (app) {


  app.get("/", function (req, res) {
    res.status(200).send({ message: 'Welcome to API' });
  });

  app.get("/user", function (req, res) {
    var data = ({
      firstName: faker.name.firstName(),
      lastName: faker.name.lastName(),
      
    });
    res.status(200).send(data);
  });

 app.get("/users/:num", function (req, res) {
   var users = [];
   var num = req.params.num;

   if (isFinite(num) && num  > 0 ) {
     for (i = 0; i <= num-1; i++) {
       users.push({
           firstName: faker.name.firstName(),
           lastName: faker.name.lastName(),
          
        });
     }

     res.status(200).send(users);
    
   } else {
     res.status(400).send({ message: 'what is your name' });
   }

 });
}

module.exports = appRouter;

Now you can hit the route http://localhost:3000/users/1.