refactor!: drop CommonJS build and transition to pure ESM package

[Timeless0911]

Summary

• @rspack/core and @rspack/cli is now published as a pure ESM package, and its CommonJS build output has been removed.

  In Node.js v20.19.0 and later, the runtime natively supports loading ESM modules via require(). As a result, for most projects that use Rspack through its JavaScript API, this change should have no practical impact and does not require any code modifications.

  While we have ensured full compatibility for native Node.js usage, please note that tooling environments (such as TypeScript, test frameworks, or bundlers) might encounter breaking changes if you import @rspack/core using import syntax in an CommonJS project (type: "module" not set) before. You may need to adjust your code usage, tsconfig.json, or the configurations of your build/test tools to accommodate this change.

• module.hot has been replaced by import.meta.webpackHot and hot/*.js recommend to use named export in Rspack 2.0.

• tests has been updated to compatible with pure esm transition

TODO

• @rspack/browser has not been refactored which will be done in later PR
• Remove default export in hot/*.js

Related links

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).

[netlify]

✅ Deploy Preview for rspack-v2 canceled.

Name	Link
🔨 Latest commit	7809a0d
🔍 Latest deploy log	https://app.netlify.com/projects/rspack-v2/deploys/6968dd44c2f93e000821c57d

[github-actions]

Rsdoctor Bundle Diff Analysis

Found 5 projects in monorepo, 5 projects with changes.

📊 Quick Summary

Project	Total Size	Change
react-10k	5.7 MB	-
react-5k	2.7 MB	-
react-1k	825.4 KB	-
rome	986.0 KB	-
ui-components	2.1 MB	-

📋 Detailed Reports (Click to expand)

📁 react-10k

Path: ../build-tools-performance/cases/react-10k/dist/rsdoctor-data.json

⚠️ No baseline data found - Unable to perform comparison analysis

Metric	Current	Baseline	Change
📊 Total Size	5.7 MB	-	-
📄 JavaScript	5.7 MB	-	-
🎨 CSS	21.0 B	-	-
🌐 HTML	0 B	-	-
📁 Other Assets	0 B	-	-

📁 react-5k

Path: ../build-tools-performance/cases/react-5k/dist/rsdoctor-data.json

⚠️ No baseline data found - Unable to perform comparison analysis

Metric	Current	Baseline	Change
📊 Total Size	2.7 MB	-	-
📄 JavaScript	2.7 MB	-	-
🎨 CSS	21.0 B	-	-
🌐 HTML	0 B	-	-
📁 Other Assets	0 B	-	-

📁 react-1k

Path: ../build-tools-performance/cases/react-1k/dist/rsdoctor-data.json

⚠️ No baseline data found - Unable to perform comparison analysis

Metric	Current	Baseline	Change
📊 Total Size	825.4 KB	-	-
📄 JavaScript	825.4 KB	-	-
🎨 CSS	0 B	-	-
🌐 HTML	0 B	-	-
📁 Other Assets	0 B	-	-

📁 rome

Path: ../build-tools-performance/cases/rome/dist/rsdoctor-data.json

⚠️ No baseline data found - Unable to perform comparison analysis

Metric	Current	Baseline	Change
📊 Total Size	986.0 KB	-	-
📄 JavaScript	986.0 KB	-	-
🎨 CSS	0 B	-	-
🌐 HTML	0 B	-	-
📁 Other Assets	0 B	-	-

📁 ui-components

Path: ../build-tools-performance/cases/ui-components/dist/rsdoctor-data.json

⚠️ No baseline data found - Unable to perform comparison analysis

Metric	Current	Baseline	Change
📊 Total Size	2.1 MB	-	-
📄 JavaScript	2.0 MB	-	-
🎨 CSS	83.0 KB	-	-
🌐 HTML	0 B	-	-
📁 Other Assets	0 B	-	-

Generated by Rsdoctor GitHub Action

[github-actions]

📦 Binary Size-limit

Comparing 7809a0d to chore(lint): bump @rslint/core to 0.2.0 and enable default-param-last rule (#12746) by senze.fan

🎉 Size decreased by 471.25KB from 48.03MB to 47.57MB (⬇️0.96%)

[codspeed-hq]

Merging this PR will not alter performance

✅ 16 untouched benchmarks
⏩ 1 skipped benchmark¹

---

_{Comparing pure-esm (7809a0d) with v2 (a0a802b)²}

Footnotes

1. 1 benchmark was skipped, so the baseline result was used instead. If it was deleted from the codebase, click here and archive it to remove it from the performance reports. ↩

2. No successful run was found on v2 (9fca97e) during the generation of this report, so a0a802b was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

[chenjiahan]

This PR should be broken down into 2-3 smaller PRs.