@babel/plugin-transform-classes

What is @babel/plugin-transform-classes?

The @babel/plugin-transform-classes package is a plugin for Babel that transforms ES2015+ class syntax into equivalent ES5 code. This is useful for ensuring compatibility with environments that do not support the latest JavaScript features.

What are @babel/plugin-transform-classes's main functionalities?

Class transformation

Transforms ES2015+ class syntax into equivalent ES5 constructor functions with prototype methods.

{"class MyClass { constructor(name) { this.name = name; } greet() { return 'Hello, ' + this.name; } } }

Super calls

Handles 'super' calls and transforms them into appropriate ES5 code that calls the parent class constructor or methods.

{"class ChildClass extends ParentClass { constructor(name) { super(name); } } }

Static methods

Transforms static methods in classes to static methods on the constructor function in ES5.

{"class MyClass { static myStaticMethod() { return 'I am static'; } } }

Instance properties

Transforms class instance properties into assignments within the constructor function.

{"class MyClass { myProperty = 'default value'; } }

Other packages similar to @babel/plugin-transform-classes

@babel/plugin-transform-arrow-functions

Transforms ES2015+ arrow functions into equivalent ES5 function expressions. Similar in that it provides transformation of modern JavaScript features to ES5, but focuses on arrow functions instead of classes.

@babel/plugin-transform-destructuring

Transforms ES2015+ destructuring assignments and parameters into equivalent ES5 code. Similar in that it provides transformation of modern JavaScript syntax to ES5, but focuses on destructuring rather than class syntax.

@babel/plugin-transform-spread

Transforms ES2015+ spread syntax for arrays and function calls into equivalent ES5 code. Similar in that it provides transformation of modern JavaScript features to ES5, but focuses on spread syntax instead of class syntax.

README

@babel/plugin-transform-classes

Compile ES2015 classes to ES5

See our website @babel/plugin-transform-classes for more information.

Install

Using npm:

npm install --save-dev @babel/plugin-transform-classes

or using yarn:

yarn add @babel/plugin-transform-classes --dev

Changelog

v7.25.9 (2024-10-22)

:bug: Bug Fix

• babel-parser, babel-template, babel-types
  • #16905 fix: Keep type annotations in syntacticPlaceholders mode (@liuxingbaoyu)
• babel-helper-compilation-targets, babel-preset-env
  • #16907 fix: support BROWSERSLIST{,_CONFIG} env (@JLHwung)
• Other
  • #16884 Analyze ClassAccessorProperty to prevent the no-undef rule (@victorenator)

:house: Internal

• babel-helper-transform-fixture-test-runner
  • #16914 remove test options flaky (@JLHwung)

:running_woman: Performance

• babel-parser, babel-types
  • #16918 perf: Make VISITOR_KEYS etc. faster to access (@liuxingbaoyu)