Planned breaking changes for Rsbuild 2.0

[chenjiahan]

This topic is used to collect and discuss breaking changes planned for Rsbuild 2.0.

Please note that we do not have a clear timeline for Rsbuild 2.0 yet.

Related: web-infra-dev/rspack#9270

[chenjiahan]

Remove the built-in webpack-bundle-analyzer

In the early versions of Rsbuild, we built-in the webpack-bundle-analyzer package for bundle size analysis. Considering that Rsdoctor now supports analyzing bundle size, we can remove this built-in functionality from @rsbuild/core to reduce the install size.

Related:

• performance.bundleAnalyze
• Rsdoctor - Bundle analysis

[chenjiahan]

Re-design performance.chunkSplit

Related:

• Is there a reason why "split-by-experience" uses splitChunks.name as the default? #5820

[chenjiahan]

Remove deprecated APIs

Configuration

• Remove source.alias, use resolve.alias instead.
• Remove source.aliasStrategy, use resolve.aliasStrategy instead.
• Remove webpackConfig from html.templateParameters, use rspackConfig instead.
• Remove htmlWebpackPlugin from html.templateParameters, use htmlPlugin instead.

Plugin API

• Remove onDevCompileDone plugin hook, use onAfterDevCompile instead.
• Remove enforce option of api.transform(), use order instead.

[chenjiahan]

Extract polyfill logic into @rsbuild/plugin-polyfill

Background

Currently, Rsbuild includes core-js as a default dependency and provides the output.polyfill option to inject polyfills automatically.

However, not all use cases require core-js. For example, projects like Rslib and Rstest rely on Rsbuild for building and testing but typically do not need runtime polyfills.

Plan

Extract the polyfill-related logic from Rsbuild core into a standalone @rsbuild/plugin-polyfill package.

Example usage:

import { pluginPolyfill } from '@rsbuild/plugin-polyfill';

export default {
  plugins: [pluginPolyfill({ mode: 'entry' })],
};

Benefits

• Smaller installation size: https://packagephobia.com/result?p=core-js
• Better extensibility, enables future polyfill solutions beyond core-js