# What changed in @rollup/plugin-typescript

> 4 changes in @rollup/plugin-typescript 9 to 12 from its official release notes, upgrade guides and advisories: 1 breaking, 1 new APIs and options. Each one cited. Sources checked 2026-10-27. HTML: https://unstale.sh/npm/@rollup/plugin-typescript/

To see which of these apply to a repository, run `npx @unstale/cli init` in it.

## @rollup/plugin-typescript 12

### New APIs and options

- Transformers receive the latest Program in watch mode. (12.3.0) — [release notes](https://github.com/rollup/plugins/blob/973054d8c7d328abf92c1445f8a0eb6e4f3d6577/packages/typescript/CHANGELOG.md#v1230)

### Behavior and default changes

- When allowJs is enabled, .js files are processed. (12.2.0) — [release notes](https://github.com/rollup/plugins/blob/973054d8c7d328abf92c1445f8a0eb6e4f3d6577/packages/typescript/CHANGELOG.md#v1220)

### Fixes and other changes

- Clears the pending program update when a build closes the watch program. (12.3.1) — [release notes](https://github.com/rollup/plugins/blob/95f1d23b3ae91457d3153e49538a7e1b094a9ca7/packages/typescript/CHANGELOG.md#v1231)

## @rollup/plugin-typescript 9

### Breaking changes

- The plugin was prepared for Rollup 3, which may affect projects using this plugin with Rollup. (9.0.0) — [release notes](https://github.com/rollup/plugins/blob/HEAD/packages/typescript/CHANGELOG.md)