@babel/helpers

What is @babel/helpers?

The @babel/helpers package is part of the Babel toolchain, which is primarily used for converting ECMAScript 2015+ code into a backwards compatible version of JavaScript in current and older browsers or environments. This specific package contains a set of functions that are used by Babel's transform plugins to avoid code duplication across generated output. These helpers are small snippets of code that perform common tasks used by the transformations, such as handling classes, spreading properties, etc.

What are @babel/helpers's main functionalities?

Class handling

This code demonstrates a helper function used by Babel to ensure that a class is only instantiated with the `new` keyword, preventing incorrect usage.

"use strict";\nfunction _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError(\"Cannot call a class as a function\"); } }\nvar MyClass = function MyClass() { _classCallCheck(this, MyClass); };

Spread properties

This helper function is used to emulate the behavior of the object spread operator `{...obj}`, allowing properties from one or more source objects to be copied into a new object.

"use strict";\nfunction _extends() { _extends = Object.assign || function (target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i]; for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { target[key] = source[key]; } } } return target; }; return _extends.apply(this, arguments); }\nvar obj = _extends({}, sourceObj, { key: 'value' });

Other packages similar to @babel/helpers

core-js

Similar to @babel/helpers, core-js is a modular standard library for JavaScript, including polyfills for ECMAScript up to 2021. While @babel/helpers provides functions to support the transformation process, core-js focuses on polyfilling new JavaScript features for older environments.

regenerator-runtime

This package provides runtime support for generators and async functions, similar to how @babel/helpers supports various syntax transformations. It's often used in conjunction with Babel for projects that use generators or async/await syntax to ensure compatibility with older environments.

README

@babel/helpers

Collection of helper functions used by Babel transforms.

See our website @babel/helpers for more information.

Install

Using npm:

npm install --save-dev @babel/helpers

or using yarn:

yarn add @babel/helpers --dev

Changelog

v7.26.0 (2024-10-25)

:rocket: New Feature

• babel-core, babel-generator, babel-parser, babel-plugin-syntax-import-assertions, babel-plugin-syntax-import-attributes, babel-preset-env, babel-standalone, babel-types
  • #16850 Enable import attributes parsing by default (@nicolo-ribaudo)
• babel-core
  • #16862 feat: support async plugin's pre/post (@timofei-iatsenko)
• babel-compat-data, babel-plugin-proposal-regexp-modifiers, babel-plugin-transform-regexp-modifiers, babel-preset-env, babel-standalone
  • #16692 Add transform-regexp-modifiers to preset-env (@JLHwung)
• babel-parser
  • #16849 feat: add startIndex parser option (@DylanPiercey)
• babel-generator, babel-parser, babel-plugin-syntax-flow
  • #16841 Always enable parsing of Flow enums (@nicolo-ribaudo)
• babel-helpers, babel-preset-typescript, babel-runtime-corejs3
  • #16794 Support import() in rewriteImportExtensions (@liuxingbaoyu)
• babel-generator, babel-parser
  • #16708 Add experimental format-preserving mode to @babel/generator (@nicolo-ribaudo)

:bug: Bug Fix

• babel-core
  • #16928 Workaround Node.js bug for parallel loading of TLA modules (@nicolo-ribaudo)
  • #16926 Fix loading of modules with TLA in Node.js 23 (@nicolo-ribaudo)

:nail_care: Polish

• babel-plugin-proposal-json-modules, babel-plugin-transform-json-modules, babel-standalone
  • #16924 Rename proposal-json-modules to transform-json-modules (@nicolo-ribaudo)

:house: Internal

• babel-code-frame, babel-highlight
  • #16896 Inline @babel/highlight in @babel/code-frame (@nicolo-ribaudo)
• babel-generator, babel-parser, babel-types
  • #16732 Add kind to TSModuleDeclaration (@liuxingbaoyu)

:running_woman: Performance

• babel-helper-module-transforms, babel-plugin-transform-modules-commonjs
  • #16882 perf: Improve module transforms (@liuxingbaoyu)