Lesson 2 / 30

When Do You Need a Transpiler?

Identify projects and scenarios where transpilation is essential.

Browser compatibility requirements

If your app must support older browsers (IE11, legacy mobile), transpilation is mandatory. Modern SPAs often skip it for users on current browsers, but build tools still include it by default.

Frontend, backend, and libraries

Frontend web apps almost always transpile. Backend Node.js apps might not if using Node 16+. Libraries transpile to support consumer environments. npm packages often include pre-transpiled code.

The default is always to transpile

Most build tools (Webpack, Vite, esbuild) include Babel or SWC by default. You configure what to transpile, not whether. It's built in.

Development vs production transpilation

In development, you might skip transpilation for faster rebuilds (browsers support modern syntax). In production, transpile for maximum compatibility.