Description of the project

Today we will integrate Typescript with our NodeJS boilerplate. If you are interested on how to setup Typescript with NodeJS then you can refer to the following articles

https://www.mohammadfaisal.dev/blog/create-nodejs-typescript-boilerplate

Get the NodeJS boilerplate

Let's first clone the boilerplate repository where we have a working NodeJS application with Typescript, EsLint and Prettier already set up. We will integrate Express on top of this

git clone https://github.com/Mohammad-Faisal/nodejs-typescript-skeleton.git

Install the dependencies

Then go inside the project and install the dependencies

cd nodejs-typescript-skeleton
yarn add express

And also the type definitions for the express module

yarn add -D @types/express

Test it out!

Go inside the src/index.ts file and import the dependencies and create a basic express application

import express, { Application, Request, Response } from 'express';

const app: Application = express();

Then let's create a basic route that will except a GET request and return a result

app.get('/', async (req: Request, res: Response): Promise<Response> => {
  return res.status(200).send({
    message: 'Hello World!',
  });
});

Then start the server on port 3000;

const PORT = 3000;

try {
  app.listen(PORT, (): void => {
    console.log(`Connected successfully on port ${PORT}`);
  });
} catch (error: any) {
  console.error(`Error occured: ${error.message}`);
}

And then run the application

yarn dev

Go ahead and hit the following URL http://localhost:3000/ and you should be greeted with the following response

{ "message": "Hello World!" }

Add Bodyparser

Now this is the bare minimum to get started with Express. But in real life we need a couple of things to get the server working properly.

to handle HTTP POST requests in express we need to install a middleware module body-parser

Let's install it first

yarn add body-parser
yarn add -D @types/body-parser

Then use it inside the index.ts file

import bodyParser from 'body-parser';

const app: Application = express();

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

And add another route to handle HTTP POST requests

app.post('/post', async (req: Request, res: Response): Promise<Response> => {
  console.log(req.body);
  return res.status(200).send({
    message: 'Hello World from post!',
  });
});

You will notice that inside the route handler we can get the body of the request by

req.body;

It's possible because of the use of body-parser

That's it! Hope you learned something new.