@babel/preset-env

What is @babel/preset-env?

The @babel/preset-env package is a Babel preset that allows you to use the latest JavaScript without needing to micromanage which syntax transforms (and optionally, browser polyfills) are needed by your target environment(s). This is done by using compatibility tables to determine which features need to be transformed or polyfilled. It helps in writing next-gen JavaScript code while ensuring backward compatibility.

What are @babel/preset-env's main functionalities?

Transforming ES2015+ syntax to be ES5 compatible

This code sample shows an ES6 arrow function, which @babel/preset-env can transform into a function expression compatible with ES5 environments.

const arrowFunction = () => console.log('Hello, World!');

Optional configuration for browser or Node.js environment targets

This JSON configuration for Babel specifies which browsers should be supported by the output code, allowing @babel/preset-env to tailor the transformations and polyfills to only what is necessary for those environments.

{
  "presets": [
    ["@babel/preset-env", {
      "targets": {
        "browsers": ["last 2 versions", "> 1%", "ie >= 11"]
      }
    }]
  ]
}

Polyfilling missing features based on the target environment

This code sample uses `Array.from` and `Set`, which may not be available in older environments. @babel/preset-env can include the necessary polyfills for these features when configured with `useBuiltIns: 'usage'`.

Array.from(new Set([1, 2, 3]));

Other packages similar to @babel/preset-env

core-js

core-js is a modular standard library for JavaScript, which includes polyfills for ECMAScript up to 2021. It's often used in conjunction with Babel to polyfill newer JavaScript features in older environments. Unlike @babel/preset-env, core-js does not handle syntax transformations but focuses on providing polyfills for language features.

esbuild

esbuild is an extremely fast JavaScript bundler and minifier. It can compile modern JavaScript syntax to older versions for compatibility purposes, similar to what @babel/preset-env does. However, esbuild is more focused on the bundling aspect and aims to be a more comprehensive build tool rather than just a transpiler.

typescript

TypeScript is a superset of JavaScript that adds static types. The TypeScript compiler can also downlevel modern JavaScript to older versions, similar to @babel/preset-env. However, TypeScript's primary focus is on type safety and it requires type annotations, whereas @babel/preset-env is purely about compiling newer JavaScript syntax to older versions.

README

@babel/preset-env

A Babel preset for each environment.

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

Install

Using npm:

npm install --save-dev @babel/preset-env

or using yarn:

yarn add @babel/preset-env --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)