Node.js

Initialization

• Install TypeScript and the TypeScript definitions for Node.js as development dependencies

mkdir my-app
cd my-app
npm init -y
npm install typescript --save-dev
npm install @types/node --save-dev

Setting Up TypeScript

• Create a tsconfig.json file to set up TypeScript compiler options

{
  "compilerOptions": {
    "target": "es5",
    "module": "commonjs",
    "lib": ["es6"],
    "allowJs": true,
    "outDir": "build",
    "rootDir": "src",
    "strict": true,
    "noImplicitAny": true,
    "esModuleInterop": true,
    "resolveJsonModule": true
  }
}

• Create a src directory and an index.ts file as the entry point of your application

mkdir src
touch src/index.ts

Nodemon Configuration

• Create a nodemon.json file to configure Nodemon to work with TypeScript

{
  "watch": ["src"],
  "ext": ".ts,.js",
  "ignore": [],
  "exec": "npx ts-node ./src/index.ts"
}

• Update your package.json scripts to include a script for starting the application in development mode with Nodemon

"scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "start:dev": "npx nodemon"
}

Running the Application

• You can start your application in development mode with the following command

npm run start:dev

Creating a Simple HTTP Server

• Add Express.js as a dependency

npm install express

• Create an Express application in src/index.ts

import express from "express";

const app = express();
const PORT = 3000;

app.get("/", (req, res) => {
  res.send("Hello World!");
});

app.listen(PORT, () => {
  console.log(`Server running on port ${PORT}`);
});