Install TypeScript in Node.js - Quick Guide

TypeScript is a powerful language that adds static typing to JavaScript. It helps catch errors early and improves code quality. This guide will show you how to install TypeScript in Node.js.

Prerequisites

Before installing TypeScript, ensure you have Node.js installed. You can check by running node -v in your terminal. If not, download it from the official Node.js website.

node -v

You should see the Node.js version. If not, install Node.js first.

Install TypeScript Globally

To use TypeScript across all projects, install it globally. Run the following command in your terminal.

npm install -g typescript

This installs TypeScript globally on your system. You can verify the installation by checking the version.

tsc -v

You should see the TypeScript version. If not, check your npm installation.

Install TypeScript Locally

For project-specific installations, add TypeScript as a dev dependency. Navigate to your project folder and run.

npm install typescript --save-dev

This adds TypeScript to your devDependencies in package.json. It ensures TypeScript is only used for this project.

Initialize TypeScript in Your Project

After installation, initialize a TypeScript configuration file. Run the following command.

tsc --init

This creates a tsconfig.json file. It contains compiler options for your TypeScript project.

Configure TypeScript

Open tsconfig.json to customize settings. Here’s a basic example.

{
  "compilerOptions": {
    "target": "es6",
    "module": "commonjs",
    "outDir": "./dist",
    "rootDir": "./src",
    "strict": true
  }
}

This configures TypeScript to compile to ES6, use CommonJS modules, and output files to a dist folder.

Write a TypeScript Example

Create a src folder and add a index.ts file. Here’s a simple example.

// Define a function with TypeScript types
function greet(name: string): string {
  return `Hello, ${name}!`;
}

console.log(greet("World"));

This function uses TypeScript’s static typing to ensure name is a string.

Compile TypeScript to JavaScript

Run the TypeScript compiler to convert your code to JavaScript. Use this command.

tsc

This compiles all .ts files in the src folder to .js files in the dist folder.

Run Your TypeScript Code

After compilation, run the generated JavaScript file with Node.js.

node dist/index.js

You should see the output Hello, World! in your terminal.

Automate Compilation

To avoid manually running tsc, use the --watch flag. It recompiles files on changes.

tsc --watch

This is useful during development. For more automation, consider tools like Nodemon.

Integrate with Other Tools

TypeScript works well with tools like Webpack and ESLint. These enhance your development workflow.

Conclusion

Installing TypeScript in Node.js is simple. It improves code quality and developer experience. Follow this guide to set it up for your projects.

For more Node.js guides, check our tutorials on React and Prettier.