Getting Started with tsup: Build Your TypeScript Library Today

Getting Started with tsup: Build Your TypeScript Library Today

The JavaScript ecosystem is brimming with tools for building and bundling libraries, but choosing the right one can be overwhelming. For TypeScript library authors, tsup emerges as a compelling option, offering a streamlined experience with exceptional performance. This article dives deep into tsup, exploring its features, advantages, and providing a comprehensive guide to get you started building your TypeScript library today.

What is tsup?

tsup is a modern, fast, and zero-configuration bundler specifically designed for building TypeScript libraries. Leveraging esbuild under the hood, it boasts impressive speed and efficiency. It simplifies the build process by providing sensible defaults, allowing developers to focus on writing code rather than wrestling with complex configurations.

Why Choose tsup?

Several factors contribute to tsup‘s popularity:

• Blazing Fast Speed: Powered by esbuild, tsup significantly outperforms traditional bundlers like Webpack and Rollup, drastically reducing build times.
• Zero Configuration: tsup requires minimal configuration, often none at all. It automatically detects your project’s entry points and generates optimized output.
• TypeScript Support: Seamlessly integrates with TypeScript, allowing you to directly bundle your .ts and .tsx files without additional setup.
• Multiple Output Formats: Supports various output formats, including CommonJS, ESM, and IIFE, catering to different consumption needs.
• Tree Shaking: Eliminates unused code, resulting in smaller bundle sizes and improved performance.
• Code Splitting: Supports code splitting, allowing you to break your library into smaller chunks for optimized loading.
• Source Maps: Generates source maps for easier debugging.
• Extensible with Plugins: Offers a plugin system for adding custom functionalities.
• Shimming Node.js built-in modules: Provides automatic shimming for Node.js built-ins, enabling seamless usage in browser environments.
• Clean and Simple API: A straightforward API makes it easy to learn and use.

Getting Started with tsup:

Let’s walk through a practical example to demonstrate how to use tsup:

1. Project Setup:

Create a new directory for your library and initialize a Node.js project:

bash
mkdir my-ts-library
cd my-ts-library
npm init -y

1. Install Dependencies:

Install tsup and TypeScript:

bash
npm install tsup typescript --save-dev

1. Configure TypeScript:

Create a tsconfig.json file in your project root:

json
{
"compilerOptions": {
"target": "es2020",
"module": "esnext",
"declaration": true,
"outDir": "dist",
"strict": true,
"esModuleInterop": true
}
}

1. Write Your Library Code:

Create a src/index.ts file and add your library code:

``typescript
export function greet(name: string): string {
returnHello, ${name}!`;
}

export const version = ‘1.0.0’;
“`

1. Build with tsup:

Add a build script to your package.json:

json
{
"scripts": {
"build": "tsup src/index.ts"
}
}

Now, run the build script:

bash
npm run build

tsup will generate the bundled files in the dist directory.

Advanced Usage:

tsup offers various options for customizing the build process:

• Multiple Entry Points:

bash
tsup src/index.ts src/utils.ts

• Specify Output Format:

bash
tsup src/index.ts --format cjs,esm

• Custom Output Directory:

bash
tsup src/index.ts --out-dir lib

• External Dependencies:

bash
tsup src/index.ts --external react

• Target Environment:

bash
tsup src/index.ts --target node16

• Sourcemap Generation:

bash
tsup src/index.ts --sourcemap

• Shimming Node.js modules:

bash
tsup src/index.ts --platform browser

• Watch Mode:

bash
tsup src/index.ts --watch

• Using Plugins:

tsup supports plugins to extend its functionalities. For example, you can use the @rollup/plugin-replace plugin to replace environment variables:

bash
npm install @rollup/plugin-replace --save-dev

Then, create a tsup.config.ts file:

“`typescript
import { defineConfig } from ‘tsup’;
import replace from ‘@rollup/plugin-replace’;

export default defineConfig({
entry: [‘src/index.ts’],
format: [‘cjs’, ‘esm’],
plugins: [
replace({
preventAssignment: true,
values: {
DEV: process.env.NODE_ENV === ‘development’,
},
}),
],
});

“`

Example: Building a React Component Library:

Let’s illustrate how to build a React component library using tsup:

1. Install React dependencies:

bash
npm install react react-dom --save

1. Create a React component:

“`typescript
// src/Button.tsx
import * as React from ‘react’;

interface ButtonProps {
children: React.ReactNode;
onClick: () => void;
}

export const Button: React.FC = ({ children, onClick }) => {
return (

{children}

);
};
“`

1. Build with tsup:

bash
tsup src/Button.tsx --format esm --external react --dts

The --dts flag generates TypeScript declaration files, crucial for consumers of your library.

Conclusion:

tsup provides a streamlined and efficient solution for building TypeScript libraries. Its speed, simplicity, and robust features make it a compelling alternative to more complex bundlers. By leveraging its sensible defaults and powerful customization options, you can significantly reduce build times and focus on crafting high-quality libraries. This comprehensive guide has equipped you with the knowledge and practical examples to get started with tsup and build your next TypeScript library today. Experiment with its features, explore the plugin ecosystem, and discover the benefits of this powerful tool. As the JavaScript landscape continues to evolve, tsup stands out as a valuable asset for any TypeScript developer.