Welcome to the World of babel-cli

Babel is a powerful tool that helps you write code in the latest version of JavaScript while ensuring compatibility with older environments. The babel-cli package allows you to use Babel from the command line to transform your JavaScript code. Below are some important APIs and examples to get you started with babel-cli.

Installation

  npm install -g @babel/cli @babel/core

Transform Files

Use babel-cli to transform files:

  babel src --out-dir lib

Watch Mode

Automatically recompile files on change:

  babel src --out-dir lib --watch

Source Maps

Generate source maps while transforming files:

  babel src --out-dir lib --source-maps

Ignore Files

Ignore specific files or directories:

  babel src --out-dir lib --ignore \"src/**/*.spec.js\"

Extensions

Compile files with specific extensions:

  babel src --out-dir lib --extensions \".ts,.tsx\"

Config File

Specify a custom babel configuration file:

  babel src --out-dir lib --config-file ./custom.babelrc

Copy Files

Copy non-compilable files to the output directory:

  babel src --out-dir lib --copy-files

Verbose

Enable detailed output:

  babel src --out-dir lib --verbose

App Example

Below is an example of using babel-cli in an application:

  .
  ├── package.json
  ├── src
  │   ├── index.js
  │   ├── util.js
  ├── .babelrc
  └── lib (output folder)

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

  // src/index.js
  import { helper } from './util';

  const message = 'Hello, Babel!';
  console.log(helper(message));

  // src/util.js
  export function helper(text) {
    return text.toUpperCase();
  }

  // Command to compile ES6 to ES5
  babel src --out-dir lib