Transpiling with Babel – ES6 → ES5

Babel converts modern JavaScript into a version compatible with older browsers.

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

.babelrc

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

Run:

npx babel src --out-dir lib

---

Example: Optional chaining (needs Babel)

const name = user?.profile?.name ?? 'Guest';

Babel will transform it to safe property checks for browsers that don’t support the syntax.