@babel/runtime

What is @babel/runtime?

The @babel/runtime package is a library that includes Babel modular runtime helpers and a version of regenerator-runtime. It is used to avoid polluting the global scope and to reduce the size of the compiled output by deduplicating helper functions that are commonly used by Babel-transpiled code. It is particularly useful when building libraries or applications that need to be optimized for size and scope isolation.

What are @babel/runtime's main functionalities?

Modularized Helpers

This feature allows you to use Babel's helper functions in a modular way, without including them in every file that needs them, thus reducing redundancy and file size.

import _classCallCheck from '@babel/runtime/helpers/classCallCheck';

class MyClass {
  constructor() {
    _classCallCheck(this, MyClass);
    // class body
  }
}

Regenerator Runtime

Includes a version of the regenerator runtime to enable the use of async/await and generator functions in environments that do not natively support them.

import 'regenerator-runtime/runtime';

async function asyncCall() {
  await someAsyncFunction();
}

Other packages similar to @babel/runtime

core-js

Similar to @babel/runtime, core-js is a modular standard library for JavaScript, which includes polyfills for ECMAScript features. It is often used in conjunction with Babel to ensure that newer language features will work in older environments. It is more comprehensive than @babel/runtime but can lead to larger bundle sizes if not used carefully.

tslib

tslib is a runtime library for TypeScript that includes helper functions similar to those in @babel/runtime. It is used to support features from TypeScript such as async/await, spread operators, and others without duplicating code. It is specific to TypeScript, whereas @babel/runtime is used with Babel and can be used with JavaScript or TypeScript.

README

@babel/runtime

babel's modular runtime helpers

See our website @babel/runtime for more information.

Install

Using npm:

npm install --save @babel/runtime

or using yarn:

yarn add @babel/runtime 

Changelog

v7.15.3 (2021-08-11)

:eyeglasses: Spec Compliance

• babel-helpers, babel-plugin-transform-classes
  • #13571 Derived constructors should not be allowed to return primitives (@dhrubesh)

:bug: Bug Fix

• babel-parser
  • #13659 Fix parse error when using named import "as" with flow parser (@doing-art)
  • #13655 [flow] Fix parsing of arrows in conditional expressions in parentheses (@nicolo-ribaudo)
  • #13645 Disallow <T>(a => b) when parsing Flow (@nicolo-ribaudo)
  • #13657 fix(parser): add attachComment to ParserOptions type (@sosukesuzuki)

:house: Internal

• #13643 Use @babel/eslint-parser/experimental-worker for our own repo (@nicolo-ribaudo)

:running_woman: Performance

• babel-parser
  • #13652 perf: minor tokenizer tweaks (@lightmare)
• babel-register
  • #13654 Reduce stat calls in register (@overlookmotel)