@babel/register

What is @babel/register?

The @babel/register npm package is a Babel hook that automatically compiles files on the fly when they are required. It is primarily used during development to compile JavaScript files using Babel as soon as they are imported, which allows developers to write modern JavaScript without worrying about compatibility with the current Node.js environment.

What are @babel/register's main functionalities?

On-the-fly ES6/ESNext compilation

Automatically compiles ES6/ESNext files when they are required. This allows you to use new JavaScript features without pre-compiling your code.

require('@babel/register');
require('./my-es6-script.js');

Custom Babel configurations

Allows you to specify custom Babel configurations, such as presets and plugins, to be applied when compiling your JavaScript files.

require('@babel/register')({
  presets: ['@babel/preset-env'],
  plugins: ['@babel/plugin-transform-runtime']
});
require('./my-custom-babel-config-script.js');

Ignore specific files or directories

Provides an option to ignore specific files or directories during the compilation process, which can improve performance by skipping unnecessary files.

require('@babel/register')({
  ignore: [/node_modules/]
});
require('./my-script.js');

Source map support

Supports inline source maps, which can be useful for debugging by allowing you to trace back to the original source code.

require('@babel/register')({
  sourceMaps: 'inline'
});
require('./my-script-with-source-maps.js');

Other packages similar to @babel/register

ts-node

Similar to @babel/register, ts-node provides on-the-fly compilation for TypeScript files. It is specifically designed for TypeScript and includes type checking, whereas @babel/register is more general-purpose for JavaScript with Babel transformations.

esm

The esm package is a lightweight runtime that allows you to use ES modules in Node.js. It offers similar on-the-fly compilation for ES module syntax but does not include the wide range of JavaScript feature transformations that Babel provides.

pirates

Pirates is a more generic module that allows you to add hooks for transforming files on the fly. While it doesn't provide the transformations itself, it can be used to implement similar functionality to @babel/register by plugging in your own transform function or using it with Babel.

require-extension-hooks

This package is designed to hook into the require function and transform files on-the-fly. It is similar to @babel/register but is more flexible as it allows you to hook into any file extension and apply custom transformations.

README

@babel/register

babel require hook

See our website @babel/register for more information or the issues associated with this package.

Install

Using npm:

npm install --save-dev @babel/register

or using yarn:

yarn add @babel/register --dev

Changelog

v7.25.7 (2024-10-02)

:bug: Bug Fix

• babel-helper-validator-identifier
  • #16825 fix: update identifier to unicode 16 (@JLHwung)
• babel-traverse
  • #16814 fix: issue with node path keys updated on unrelated paths (@DylanPiercey)
• babel-plugin-transform-classes
  • #16797 Use an inclusion rather than exclusion list for super() check (@nicolo-ribaudo)
• babel-generator
  • #16788 Fix printing of TS infer in compact mode (@nicolo-ribaudo)
  • #16785 Print TS type annotations for destructuring in assignment pattern (@nicolo-ribaudo)
  • #16778 Respect [no LineTerminator here] after nodes (@nicolo-ribaudo)

:nail_care: Polish

• babel-types
  • #16852 Add deprecated JSDOC for fields (@liuxingbaoyu)

:house: Internal

• babel-core
  • #16820 Allow sync loading of ESM when --experimental-require-module (@nicolo-ribaudo)
• babel-helper-compilation-targets, babel-helper-plugin-utils, babel-preset-env
  • #16858 Add browserslist config to external dependency (@JLHwung)
• babel-plugin-proposal-destructuring-private, babel-plugin-syntax-decimal, babel-plugin-syntax-import-reflection, babel-standalone
  • #16809 Archive syntax-import-reflection and syntax-decimal (@nicolo-ribaudo)
• babel-generator
  • #16779 Simplify logic for [no LineTerminator here] before nodes (@nicolo-ribaudo)

:running_woman: Performance

• babel-plugin-transform-typescript
  • #16875 perf: Avoid extra cloning of namespaces (@liuxingbaoyu)
• babel-types
  • #16842 perf: Improve @babel/types builders (@liuxingbaoyu)
  • #16828 Only access BABEL_TYPES_8_BREAKING at startup (@nicolo-ribaudo)