# Babel: what changed from 7 to 8

- Product: Babel (https://whatsnew.fyi/product/babel)
- Vendor: Babel
- Range: changelog entries numbered after v7.29.8 up to and including v8.0.4, stable releases only
- Entries below: 5 releases (newest first)
- Resolved: 7 is v7.29.8 and 8 is v8.0.4, the newest stable release of each major we track
- Carrying security changes: 0 · CVEs mentioned: 0 · Mentioning breaking changes: 2 · Removing or deprecating something: 2
- Page: https://whatsnew.fyi/product/babel/compare/7...8

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

## What changed (14 changes, grouped by kind)

### Changed

#### v8.0.0 (2026-06-16)

- Only extract source map comments at the end of the file for improved performance
- Fallback to assuming ESM support with `modules: auto`

### Fixed

#### v8.0.4 (2026-07-09)

- Disallow `declare module M {}` in TypeScript
- Forbid `let x!` and `let x! =` syntax in TypeScript
- `replaceWith` in `Visitor#exit` should not stop traversal

#### v8.0.3 (2026-06-27)

- Remove `isTSX` from `babel-plugin-syntax-typescript` types
- Use `runtime: 'classic'` in the browser for React in babel-standalone

#### v8.0.2 (2026-06-20)

- Use the @babel/core version when asserting version in @babel/standalone
- Avoid double escaping slash in identifier validation

#### v8.0.0 (2026-06-16)

- Improve new callee parens check in generator
- Support __proto__ as an export name in systemjs plugin

### Removed

#### v8.0.1 (2026-06-17)

- Remove preset-env's useBuiltIns option

#### v8.0.0 (2026-06-16)

- Remove corejs exports for `@babel/runtime-corejs3`
- Remove `locations: "packed"` from babel-parser

## Release notes

### v8.0.4

- Date: 2026-07-09
- Version: v8.0.4
- Original notes: https://github.com/babel/babel/releases/tag/v8.0.4
- Permalink: https://whatsnew.fyi/product/babel/releases/v8.0.4

- **fixed** — Disallow `declare module M {}` in TypeScript
- **fixed** — Forbid `let x!` and `let x! =` syntax in TypeScript
- **fixed** — `replaceWith` in `Visitor#exit` should not stop traversal

##### v8.0.4 (2026-07-09)

###### :eyeglasses: Spec Compliance
* `babel-parser`, `babel-plugin-transform-typescript`
  * [#18120](https://github.com/babel/babel/pull/18120) fix(parser): disallow `declare module M {}` ([@JLHwung](https://github.com/JLHwung))
* `babel-generator`, `babel-parser`, `babel-plugin-transform-typescript`
  * [#18100](https://github.com/babel/babel/pull/18100) fix(parser): forbid let x! and let x! = ([@JLHwung](https://github.com/JLHwung))

###### :bug: Bug Fix
* `babel-traverse`
  * [#18122](https://github.com/babel/babel/pull/18122) fix: `replaceWith` in `Visitor#exit` should not stop traversal ([@liuxingbaoyu](https://github.com/liuxingbaoyu))

###### :house: Internal
* `babel-helper-validator-identifier`
  * [#18084](https://github.com/babel/babel/pull/18084) refactor: Shrink validator identifier size ([@JLHwung](https://github.com/JLHwung))

###### Committers: 4
- Babel Bot ([@babel-bot](https://github.com/babel-bot))
- Huáng Jùnliàng ([@JLHwung](https://github.com/JLHwung))
- Nicolò Ribaudo ([@nicolo-ribaudo](https://github.com/nicolo-ribaudo))
- [@liuxingbaoyu](https://github.com/liuxingbaoyu)

### v8.0.3

- Date: 2026-06-27
- Version: v8.0.3
- Original notes: https://github.com/babel/babel/releases/tag/v8.0.3
- Permalink: https://whatsnew.fyi/product/babel/releases/v8.0.3

- **fixed** — Remove `isTSX` from `babel-plugin-syntax-typescript` types
- **fixed** — Use `runtime: 'classic'` in the browser for React in babel-standalone

##### v8.0.3 (2026-06-27)

###### :bug: Bug Fix
* `babel-core`, `babel-plugin-syntax-typescript`
  * [#18089](https://github.com/babel/babel/pull/18089) fix: Remove `isTSX` from `babel-plugin-syntax-typescript` types ([@liuxingbaoyu](https://github.com/liuxingbaoyu))
* `babel-standalone`
  * [#18086](https://github.com/babel/babel/pull/18086) fix: Use `runtime: 'classic'` in the browser for React ([@liuxingbaoyu](https://github.com/liuxingbaoyu))

###### Committers: 2
- Nicolò Ribaudo ([@nicolo-ribaudo](https://github.com/nicolo-ribaudo))
- [@liuxingbaoyu](https://github.com/liuxingbaoyu)

### v8.0.2

- Date: 2026-06-20
- Version: v8.0.2
- Original notes: https://github.com/babel/babel/releases/tag/v8.0.2
- Permalink: https://whatsnew.fyi/product/babel/releases/v8.0.2

- **fixed** — Use the @babel/core version when asserting version in @babel/standalone
- **fixed** — Avoid double escaping slash in identifier validation

##### v8.0.2 (2026-06-18)

###### :bug: Bug Fix
* Other
  * [#18083](https://github.com/babel/babel/pull/18083) Use the `@babel/core` version when asserting version in `@babel/standalone` ([@nicolo-ribaudo](https://github.com/nicolo-ribaudo))
* `babel-helper-validator-identifier`
  * [#18075](https://github.com/babel/babel/pull/18075) fix(identifier): avoid double escaping slash ([@JLHwung](https://github.com/JLHwung))

###### :house: Internal
* `babel-plugin-proposal-decorators`, `babel-plugin-transform-regenerator`, `babel-preset-env`
  * [#18081](https://github.com/babel/babel/pull/18081) Update `@babel/preset-modules` and polyfill packages ([@nicolo-ribaudo](https://github.com/nicolo-ribaudo))

###### Committers: 2
- Huáng Jùnliàng ([@JLHwung](https://github.com/JLHwung))
- Nicolò Ribaudo ([@nicolo-ribaudo](https://github.com/nicolo-ribaudo))

### v8.0.1

- Date: 2026-06-17
- Version: v8.0.1
- Original notes: https://github.com/babel/babel/releases/tag/v8.0.1
- Permalink: https://whatsnew.fyi/product/babel/releases/v8.0.1

- **removed** — Remove preset-env's useBuiltIns option

##### v8.0.1 (2026-06-17)

This release includes a breaking change that was in the Babel 8 migration guide's [Getting ready](https://babeljs.io/docs/v8-migration/#getting-ready) section and [in the release post](https://babeljs.io/blog/2026/06/16/8.0.0/#extract-polyfill-injection-to-separate-packages), but the actual removal of the feature from the codebase was accidentally not complete.

###### :boom: Breaking Change
* `babel-core`, `babel-plugin-transform-object-rest-spread`, `babel-plugin-transform-runtime`, `babel-preset-env`, `babel-standalone`
  * [#18079](https://github.com/babel/babel/pull/18079) Actually remove `preset-env`'s `useBuiltIns` ([@nicolo-ribaudo](https://github.com/nicolo-ribaudo))

###### Committers: 2
- Huáng Jùnliàng ([@JLHwung](https://github.com/JLHwung))
- Nicolò Ribaudo ([@nicolo-ribaudo](https://github.com/nicolo-ribaudo))

### v8.0.0

- Date: 2026-06-16
- Version: v8.0.0
- Original notes: https://github.com/babel/babel/releases/tag/v8.0.0
- Permalink: https://whatsnew.fyi/product/babel/releases/v8.0.0

- **changed** — Only extract source map comments at the end of the file for improved performance
- **changed** — Fallback to assuming ESM support with `modules: auto`
- **removed** — Remove corejs exports for `@babel/runtime-corejs3`
- **removed** — Remove `locations: "packed"` from babel-parser
- **fixed** — Improve new callee parens check in generator
- **fixed** — Support __proto__ as an export name in systemjs plugin

##### v8.0.0 (2026-06-16)

**NOTE:** The changelog below is relative to v8.0.0-rc.6. You can find a summary of all the breaking changes shipped in the Babel 8 release line in the [migration guide for users](https://babeljs.io/docs/v8-migration) and [migration guide for plugin developers](https://babeljs.io/docs/v8-migration-api).

Read the release blog post at http://babeljs.io/blog/2026/06/16/8.0.0!

###### :eyeglasses: Spec Compliance
* `babel-core`
  * [#18039](https://github.com/babel/babel/pull/18039) perf: Only extract source map comments at the end of the file ([@liuxingbaoyu](https://github.com/liuxingbaoyu))

###### :boom: Breaking Change
* `babel-cli`, `babel-node`, `babel-plugin-proposal-decorators`, `babel-plugin-transform-classes`, `babel-plugin-transform-function-name`, `babel-plugin-transform-modules-commonjs`, `babel-plugin-transform-object-rest-spread`, `babel-plugin-transform-parameters`, `babel-plugin-transform-react-constant-elements`, `babel-plugin-transform-regenerator`, `babel-preset-env`, `babel-register`
  * [#18069](https://github.com/babel/babel/pull/18069) Fallback to assuming ESM support with `modules: auto` ([@nicolo-ribaudo](https://github.com/nicolo-ribaudo))
* `babel-plugin-transform-runtime`, `babel-runtime-corejs3`, `babel-runtime`
  * [#18036](https://github.com/babel/babel/pull/18036) Remove corejs exports for `@babe/runtime-corejs3` ([@liuxingbaoyu](https://github.com/liuxingbaoyu))
* `babel-parser`
  * [#18034](https://github.com/babel/babel/pull/18034) Remove `locations: "packed"` ([@liuxingbaoyu](https://github.com/liuxingbaoyu))

###### :bug: Bug Fix
* `babel-generator`
  * [#18046](https://github.com/babel/babel/pull/18046) fix(generator): improve new callee parens check ([@JLHwung](https://github.com/JLHwung))
* `babel-plugin-transform-modules-systemjs`
  * [#18032](https://github.com/babel/babel/pull/18032) fix(systemjs): support __proto__ as an export name ([@JLHwung](https://github.com/JLHwung))

###### :memo: Documentation
* [#18070](https://github.com/babel/babel/pull/18070) Add EOL date for Babel 7 (end of June 2027) to SECURITY.md ([@nicolo-ribaudo](https://github.com/nicolo-ribaudo))

###### :house: Internal
* [#18018](https://github.com/babel/babel/pull/18018) ci: enforce yarn integrity ([@JLHwung](https://github.com/JLHwung))

###### :running_woman: Performance
* `babel-core`
  * [#18039](https://github.com/babel/babel/pull/18039) perf: Only extract source map comments at the end of the file ([@liuxingbaoyu](https://github.com/liuxingbaoyu))

###### Committers: 6
- Babel Bot ([@babel-bot](https://github.com/babel-bot))
- Huáng Jùnliàng ([@JLHwung](https://github.com/JLHwung))
- James Garbutt ([@43081j](https://github.com/43081j))
- Nicolò Ribaudo ([@nicolo-ribaudo](https://github.com/nicolo-ribaudo))
- Sandy Chen ([@sandy2008](https://github.com/sandy2008))
- [@liuxingbaoyu](https://github.com/liuxingbaoyu)