How to setup your NodeJs project with TypeScript?

I am going to teach you how to setup your nodejs project with typescript.

Why TypeScript?

• TypeScript is JavaScript with static typing, allowing you to define the type of variables at compile-time. This helps you to catch errors during development and reducing run-time bugs.

• Other developers can understand the expected type of variables and function parameters making it easier to collaborate.

• Excellent support for modern IDE's like VS Code give you features like autocompletion and real-time error checking.

• Frameworks like nextjs, vite come with built in typescript compiler although you need to configure it in a node project.

How to?

First start with initializing a node project -

npm init -y

This will create a package.json file. Now install typescript as a dev dependency with the command

npm install -D typescript

In your package.json file add

{
  "name": "server",
  "version": "1.0.0",
  "description": "",
  "main": "index.ts",
  "scripts": {
    "build": "tsc" //This script object over here it converts the javascript code to typescript.
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "typescript": "^5.3.3"
  },
}

Now install the types for node since it won't be able to find it's type declaration. Run

npm install ts-node

Now create a src folder and create an index.ts file inside it.

Once done create a tsconfig.json file outside. In the file add

{
    "compilerOptions": {
        "module": "NodeNext",
        "moduleResolution": "NodeNext",
        "target": "ES2020",
        "baseUrl": "src",
        "rootDir": "src",//This is the root directory
        "outDir": "dist", //This is the directory where the converted javascript code will live 
        "sourceMap": true,
        "noImplicitAny": true,
    },
    "include": ["src/**/*"],
}

Now run

npm run build

This will create a dist folder where you can see the converted javascript code.

NOTE :

Whenever you install dependencies like express, cors etc. Do install their types as well

npm install express
npm install -D @types/express