Typescript Transpiler Setup

To master working with TypeScript-compatible transpilers like Babel, SWC, and Sucrase, follow this step-by-step approach: 1. Understanding the Role of Transpilers Transpilers convert TypeScript (TS) code into JavaScript (JS) that can run in different environments (browsers, Node.js). The main reasons for using a transpiler instead of tsc (TypeScript compiler) include: Faster compilation (SWC and Sucrase are much faster than tsc). More flexible configurations (especially Babel for advanced JavaScript transformations). Compatibility with build tools like Webpack, Vite, and Esbuild. 2. Setting Up and Using Different Transpilers A. Using Babel with TypeScript Babel is widely used for JavaScript transformations and can be configured to work with TypeScript. Steps to set up Babel for TypeScript Initialize a project mkdir babel-ts-project && cd babel-ts-project npm init -y Install Babel and TypeScript dependencies npm install --save-dev @babel/core @babel/cli @babel/preset-env @babel/preset-typescript Create a Babel configuration file (babel.config.json) { "presets": ["@babel/preset-env", "@babel/preset-typescript"] } Create a TypeScript file (index.ts) const greet = (name: string): string => { return `Hello, ${name}!`; }; console.log(greet("TypeScript with Babel")); Transpile the code using Babel npx babel index.ts --out-file index.js Run the transpiled JavaScript node index.js ✅ Babel doesn't check types: Unlike tsc, Babel only removes TypeScript syntax but does not enforce type checking. You need to use tsc --noEmit separately for type checking. B. Using SWC (Speedy Web Compiler) SWC is a Rust-based transpiler that is significantly faster than Babel. Steps to set up SWC for TypeScript Install SWC CLI and dependencies npm install --save-dev @swc/core @swc/cli Create an SWC configuration file (.swcrc) { "jsc": { "parser": { "syntax": "typescript" }, "target": "es2022" } } Transpile the TypeScript file npx swc index.ts -o index.js Run the output node index.js ✅ SWC is much faster than Babel and also supports type stripping. However, like Babel, it does not perform type checking. C. Using Sucrase Sucrase is a lightweight TypeScript transpiler optimized for development. Steps to set up Sucrase Install Sucrase npm install --save-dev sucrase Transpile TypeScript to JavaScript npx sucrase ./index.ts --transform-typescript --out-dir dist Run the output node dist/index.js ✅ Sucrase is the fastest among the three but is designed only for development. It lacks many transformation features available in Babel or SWC. 3. Comparing Babel, SWC, and Sucrase Feature Babel SWC Sucrase Speed Slow Fast Very Fast Type Removal ✅ ✅ ✅ Type Checking ❌ (needs tsc --noEmit) ❌ ❌ Advanced Transformations ✅ ⚠️ (limited) ❌ Suitable for Production ✅ ✅ ❌ (dev only) 4. Type Checking Strategy Since none of these transpilers perform type checking, you should use tsc separately: npx tsc --noEmit This ensures type safety without slowing down transpilation. 5. Integration with Build Tools Webpack + Babel Install required packages: npm install --save-dev babel-loader webpack webpack-cli @babel/core @babel/preset-env @babel/preset-typescript Configure webpack.config.js: module.exports = { entry: "./src/index.ts", module: { rules: [ { test: /\.ts$/, use: "babel-loader", exclude: /node_modules/, }, ], }, resolve: { extensions: [".ts", ".js"] }, output: { filename: "bundle.js" }, }; Vite + SWC Install Vite with SWC: npm create vite@latest my-app --template react-ts cd my-app npm install Vite automatically uses SWC for TypeScript transpilation. Conclusion Use Babel if you need advanced transformations and compatibility with plugins. Use SWC if you want fast production-ready builds. Use Sucrase if you need the fastest development transpilation. Always use tsc --noEmit for type checking since these transpilers do not check types.

Mar 13, 2025 - 19:35

To master working with TypeScript-compatible transpilers like Babel, SWC, and Sucrase, follow this step-by-step approach:

1. Understanding the Role of Transpilers

Transpilers convert TypeScript (TS) code into JavaScript (JS) that can run in different environments (browsers, Node.js). The main reasons for using a transpiler instead of tsc (TypeScript compiler) include:

Faster compilation (SWC and Sucrase are much faster than tsc).
More flexible configurations (especially Babel for advanced JavaScript transformations).
Compatibility with build tools like Webpack, Vite, and Esbuild.

2. Setting Up and Using Different Transpilers

A. Using Babel with TypeScript

Babel is widely used for JavaScript transformations and can be configured to work with TypeScript.

Steps to set up Babel for TypeScript

Initialize a project

   mkdir babel-ts-project && cd babel-ts-project
   npm init -y

Install Babel and TypeScript dependencies

   npm install --save-dev @babel/core @babel/cli @babel/preset-env @babel/preset-typescript

Create a Babel configuration file (babel.config.json)

   {
     "presets": ["@babel/preset-env", "@babel/preset-typescript"]
   }

Create a TypeScript file (index.ts)

   const greet = (name: string): string => {
       return `Hello, ${name}!`;
   };
   console.log(greet("TypeScript with Babel"));

Transpile the code using Babel

   npx babel index.ts --out-file index.js

Run the transpiled JavaScript

   node index.js

✅ Babel doesn't check types: Unlike tsc, Babel only removes TypeScript syntax but does not enforce type checking. You need to use tsc --noEmit separately for type checking.

B. Using SWC (Speedy Web Compiler)

SWC is a Rust-based transpiler that is significantly faster than Babel.

Steps to set up SWC for TypeScript

Install SWC CLI and dependencies

   npm install --save-dev @swc/core @swc/cli

Create an SWC configuration file (.swcrc)

   {
     "jsc": {
       "parser": {
         "syntax": "typescript"
       },
       "target": "es2022"
     }
   }

Transpile the TypeScript file

   npx swc index.ts -o index.js

Run the output

   node index.js

✅ SWC is much faster than Babel and also supports type stripping. However, like Babel, it does not perform type checking.

C. Using Sucrase

Sucrase is a lightweight TypeScript transpiler optimized for development.

Steps to set up Sucrase

Install Sucrase

   npm install --save-dev sucrase

Transpile TypeScript to JavaScript

   npx sucrase ./index.ts --transform-typescript --out-dir dist

Run the output

   node dist/index.js

✅ Sucrase is the fastest among the three but is designed only for development. It lacks many transformation features available in Babel or SWC.

3. Comparing Babel, SWC, and Sucrase

Feature	Babel	SWC	Sucrase
Speed	Slow	Fast	Very Fast
Type Removal	✅	✅	✅
Type Checking	❌ (needs `tsc --noEmit`)	❌	❌
Advanced Transformations	✅	⚠️ (limited)	❌
Suitable for Production	✅	✅	❌ (dev only)

4. Type Checking Strategy

Since none of these transpilers perform type checking, you should use tsc separately:

npx tsc --noEmit

This ensures type safety without slowing down transpilation.

5. Integration with Build Tools

Webpack + Babel

Install required packages:

   npm install --save-dev babel-loader webpack webpack-cli @babel/core @babel/preset-env @babel/preset-typescript

Configure webpack.config.js:

   module.exports = {
     entry: "./src/index.ts",
     module: {
       rules: [
         {
           test: /\.ts$/,
           use: "babel-loader",
           exclude: /node_modules/,
         },
       ],
     },
     resolve: { extensions: [".ts", ".js"] },
     output: { filename: "bundle.js" },
   };

Vite + SWC

Install Vite with SWC:

   npm create vite@latest my-app --template react-ts
   cd my-app
   npm install

Vite automatically uses SWC for TypeScript transpilation.

Conclusion

Use Babel if you need advanced transformations and compatibility with plugins.
Use SWC if you want fast production-ready builds.
Use Sucrase if you need the fastest development transpilation.
Always use tsc --noEmit for type checking since these transpilers do not check types.