@babel/plugin-transform-react-pure-annotations

What is @babel/plugin-transform-react-pure-annotations?

The @babel/plugin-transform-react-pure-annotations package is a Babel plugin designed to enhance optimization for React components by automatically annotating React components with `/*#__PURE__*/` comments. These comments signal to JavaScript bundlers and minifiers, such as Terser, that the component functions can be safely tree-shaken if they are not used. This can lead to smaller bundle sizes in production builds.

What are @babel/plugin-transform-react-pure-annotations's main functionalities?

Automatic Pure Annotation for Functional Components

Automatically adds pure annotations to functional React components, indicating that they can be safely removed if unused.

Before:
const MyComponent = () => <div>Hello World</div>;

After:
const MyComponent = /*#__PURE__*/() => <div>Hello World</div>;

Automatic Pure Annotation for Class Components

Automatically adds pure annotations to the return value of render methods in class components, aiding in their potential tree-shaking.

Before:
class MyComponent extends React.Component {
  render() {
    return <div>Hello World</div>;
  }
}

After:
class MyComponent extends React.Component {
  render() {
    return /*#__PURE__*/<div>Hello World</div>;
  }
}

Other packages similar to @babel/plugin-transform-react-pure-annotations

@babel/plugin-transform-react-inline-elements

Transforms React.createElement calls to object literals. This can improve performance by reducing the overhead of these calls at runtime. However, it does not specifically focus on tree-shaking like @babel/plugin-transform-react-pure-annotations does.

@babel/plugin-transform-react-constant-elements

Hoists element creation to the highest scope possible. This can improve performance in React applications by reducing the need to recreate the same elements on each render. While it optimizes performance, its approach is different from adding pure annotations for tree-shaking.

README

@babel/plugin-transform-react-pure-annotations

Mark top-level React method calls as pure for tree shaking

See our website @babel/plugin-transform-react-pure-annotations for more information.

Install

Using npm:

npm install --save-dev @babel/plugin-transform-react-pure-annotations

or using yarn:

yarn add @babel/plugin-transform-react-pure-annotations --dev

Changelog

v7.27.1 (2025-04-30)

:eyeglasses: Spec Compliance

• babel-parser
  • #17254 Allow using of as lexical declaration within for (@JLHwung)
  • #17230 Disallow get/set in TSPropertySignature (@JLHwung)
• babel-parser, babel-types
  • #17193 Stricter TSImportType options parsing (@JLHwung)

:bug: Bug Fix

• babel-plugin-proposal-destructuring-private, babel-plugin-proposal-do-expressions, babel-traverse
  • #17137 fix: do expressions should allow early exit (@kermanx)
• babel-helper-wrap-function, babel-plugin-transform-async-to-generator
  • #17251 Fix: propagate argument evaluation errors through async promise chain (@magic-akari)
• babel-helper-remap-async-to-generator, babel-plugin-transform-async-to-generator
  • #17231 fix apply()/call() annotated as pure (@Lacsw)
• babel-helper-fixtures, babel-parser
  • #17233 Create ChainExpression within TSInstantiationExpression (@JLHwung)
• babel-generator, babel-parser
  • #17226 Fill optional AST properties when both estree and typescript parser plugin are enabled (Part 2) (@JLHwung)
• babel-parser
  • #17224 Fill optional AST properties when both estree and typescript parser plugin are enabled (Part 1) (@JLHwung)
  • #17080 Fix start of TSParameterProperty (@JLHwung)
• babel-compat-data, babel-preset-env
  • #17228 Update firefox bugfix compat data (@JLHwung)
• babel-traverse
  • #17156 fix: Objects and arrays with multiple references should not be evaluated (@liuxingbaoyu)
• babel-generator
  • #17216 Fix: support const type parameter in generator (@JLHwung)

:nail_care: Polish

• babel-plugin-bugfix-v8-spread-parameters-in-optional-chaining, babel-plugin-proposal-decorators, babel-plugin-transform-arrow-functions, babel-plugin-transform-class-properties, babel-plugin-transform-destructuring, babel-plugin-transform-object-rest-spread, babel-plugin-transform-optional-chaining, babel-plugin-transform-parameters, babel-traverse
  • #17221 Reduce generated names size for the 10th-11th (@nicolo-ribaudo)

:house: Internal

• babel-runtime-corejs2, babel-runtime-corejs3, babel-runtime
  • #17263 Remove unused regenerator-runtime dep in @babel/runtime (@nicolo-ribaudo)
• babel-compat-data, babel-preset-env
  • #17256 Tune plugin compat data (@JLHwung)
• babel-compat-data, babel-standalone
  • #17236 migrate babel-compat-data build script to mjs (@JLHwung)
• Other
  • #17232 Bump typescript-eslint to 8.29.1 (@JLHwung)
  • #17219 test: add basic typescript-eslint integration tests (@JLHwung)
  • #17205 Inline regenerator in the relevant packages (@nicolo-ribaudo)
• babel-register
  • #16844 Migrate @babel/register to cts (@liuxingbaoyu)
• babel-cli, babel-compat-data, babel-core, babel-generator, babel-helper-compilation-targets, babel-helper-fixtures, babel-helper-module-imports, babel-helper-module-transforms, babel-helper-plugin-test-runner, babel-helper-transform-fixture-test-runner, babel-helpers, babel-node, babel-parser, babel-plugin-transform-modules-amd, babel-plugin-transform-modules-commonjs, babel-plugin-transform-modules-systemjs, babel-plugin-transform-modules-umd, babel-plugin-transform-react-display-name, babel-plugin-transform-regenerator, babel-plugin-transform-runtime, babel-plugin-transform-typeof-symbol, babel-plugin-transform-typescript, babel-preset-env, babel-register, babel-standalone, babel-types
  • #17207 Enforce node protocol import (@JLHwung)
• babel-plugin-transform-regenerator
  • #17205 Inline regenerator in the relevant packages (@nicolo-ribaudo)
  • #17205 Inline regenerator in the relevant packages (@nicolo-ribaudo)
• babel-helpers, babel-plugin-transform-async-generator-functions, babel-plugin-transform-regenerator, babel-preset-env, babel-runtime-corejs3
  • #17205 Inline regenerator in the relevant packages (@nicolo-ribaudo)
• babel-helpers, babel-plugin-transform-regenerator
  • #17205 Inline regenerator in the relevant packages (@nicolo-ribaudo)
  • #17205 Inline regenerator in the relevant packages (@nicolo-ribaudo)
• babel-helpers
  • #17205 Inline regenerator in the relevant packages (@nicolo-ribaudo)

:microscope: Output optimization

• babel-helpers, babel-plugin-transform-modules-commonjs, babel-runtime-corejs3
  • #16538 Reduce interopRequireWildcard size (@liuxingbaoyu)
• babel-helpers, babel-plugin-transform-async-generator-functions, babel-plugin-transform-regenerator, babel-preset-env, babel-runtime-corejs3
  • #17213 Reduce regeneratorRuntime size (@liuxingbaoyu)