How to use TypeScript with Next.js

Using TypeScript with Next.js is a great way to enhance type safety and improve the development experience in your Next.js projects. Here's a step-by-step guide on how to set up and use TypeScript with Next.js:

Step 1: Create a Next.js Project

If you don't already have a Next.js project, you can create one using the following command:

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npx create-next-app my-nextjs-app
cd my-nextjs-app

Step 2: Add TypeScript Dependencies

Next, you need to add TypeScript and its types for React to your project. Run the following command in your project directory:

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npm install --save-dev typescript @types/react @types/node

Step 3: Initialize TypeScript Configuration

Initialize a tsconfig.json file in the root of your project. You can create one manually or use the TypeScript CLI:

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npx tsc --init

This will generate a default tsconfig.json file. You may need to tweak it based on your project requirements.

Step 4: Rename Files to Use TypeScript Extensions

Rename your existing .js and .jsx files to use the .ts and .tsx extensions. For example, if you have a file named index.js, rename it to index.tsx.

Step 5: Update package.json

Update your package.json file to include a "scripts" entry for running TypeScript files:

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"scripts": {
  "dev": "next dev",
  "build": "next build",
  "start": "next start",
  "type-check": "tsc --noEmit",
  "lint": "eslint . --ext .tsx,.ts"
},

This includes the "type-check" script to run TypeScript type checking and a "lint" script assuming you're using ESLint.

Step 6: Install ESLint and TypeScript ESLint Plugin

If you're not already using ESLint, install it along with the TypeScript ESLint plugin:

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npm install --save-dev eslint @typescript-eslint/parser @typescript-eslint/eslint-plugin

Step 7: Configure ESLint

Create an .eslintrc.js file in the root of your project with the following content:

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module.exports = {
  parser: '@typescript-eslint/parser',
  plugins: ['@typescript-eslint'],
  extends: [
    'plugin:@typescript-eslint/recommended',
    'next',
    'next/core-web-vitals',
  ],
};

Step 8: Update Component and Page Files

Update your React components and Next.js pages to use TypeScript syntax. For example, if you have a file index.tsx, it might look like this:

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// pages/index.tsx
import React from 'react';

const HomePage: React.FC = () => {
  return (
    <div>
      <h1>Hello Next.js with TypeScript</h1>
    </div>
  );
};

export default HomePage;

Step 9: Run Your Next.js App

You can now run your Next.js app with TypeScript support using:

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npm run dev

And that's it! Your Next.js project is now set up to use TypeScript. You can continue developing your app with the benefits of TypeScript's static typing.

Remember to refer to the official documentation for Next.js and TypeScript for any additional configuration or updates:

• Next.js TypeScript Documentation
• TypeScript Documentation