core-js-compat

What is core-js-compat?

The core-js-compat package provides compatibility data for core-js, which is a modular standard library for JavaScript, including polyfills for ECMAScript up to the latest standards. It is useful for developers who need to know which features are available in core-js for a specific version of a browser or Node.js.

What are core-js-compat's main functionalities?

Compatibility Data Retrieval

Retrieve a list of features supported by core-js for a specific environment, such as Chrome 70.

const { list } = require('core-js-compat')({ targets: 'chrome 70' });

Custom Build Generation

Generate a list of core-js modules required to support a specific target, such as Internet Explorer 11, with a specific version of core-js.

const { getModulesListForTargetVersion } = require('core-js-compat');
const modulesList = getModulesListForTargetVersion({ targets: { ie: 11 }, version: '3.6' });

Other packages similar to core-js-compat

babel-polyfill

Babel-polyfill is a package that includes Babel transforms and a polyfill that includes a custom regenerator runtime and core-js. It is similar to core-js-compat in that it provides polyfills for ECMAScript features, but it is less modular and is deprecated in favor of directly including core-js and regenerator-runtime.

es6-shim

The es6-shim package provides polyfills for ECMAScript 6 (also known as ECMAScript 2015) features. It is similar to core-js-compat in providing polyfills, but it is focused only on ES6 features and does not provide the modular approach or the compatibility data that core-js-compat offers.

polyfill-service

The polyfill-service package by Financial Times provides a service that returns a set of polyfills based on the user-agent string of the browser making the request. It is similar to core-js-compat in that it aims to provide polyfills for compatibility, but it does so as a service rather than a package to include in your project.

README

core-js-compat package contains data about the necessity of core-js modules and API for getting a list of required core-js modules by browserslist query.

const {
  list,              // array of required modules
  targets,           // object with targets for each module
} = require('core-js-compat')({
  targets: '> 2.5%', // browserslist query
  filter: 'es.',     // optional filter - string-prefix, regexp or list of modules
});

console.log(targets);
/* =>
{
  'es.symbol.description': { ios: '12.0-12.1' },
  'es.array.reverse': { ios: '12.0-12.1' },
  'es.string.replace': { firefox: '63', ios: '12.0-12.1' },
  'es.string.trim': { ios: '12.0-12.1' },
  'es.promise': { firefox: '63' },
  'es.promise.finally': { firefox: '63' },
  'es.array-buffer.slice': { ios: '12.0-12.1' },
  'es.typed-array.int8-array': { ios: '12.0-12.1' },
  'es.typed-array.uint8-array': { ios: '12.0-12.1' },
  'es.typed-array.uint8-clamped-array': { ios: '12.0-12.1' },
  'es.typed-array.int16-array': { ios: '12.0-12.1' },
  'es.typed-array.uint16-array': { ios: '12.0-12.1' },
  'es.typed-array.int32-array': { ios: '12.0-12.1' },
  'es.typed-array.uint32-array': { ios: '12.0-12.1' },
  'es.typed-array.float32-array': { ios: '12.0-12.1' },
  'es.typed-array.float64-array': { ios: '12.0-12.1' },
  'es.typed-array.from': { ios: '12.0-12.1' },
  'es.typed-array.of': { ios: '12.0-12.1' }
}
*/

If you want to add new / update data about modules required for target engines, follow this instruction.

Changelog

3.2.1 - 2019.08.12

• Added a workaround for possible recursion in microtasks caused by conflicts with other Promise polyfills, #615