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feat(jest-config): add defineConfig and mergeConfig functions #15844

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@ahnpnl ahnpnl commented Sep 30, 2025 •
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Summary

Inspired from Vite and Playwright, this PR introduces 2 new functions to jest-config: defineConfig and mergeConfig.

This will greatly improve DX that developers:

  • Don't need to know which interface to use
  • Get autocomplete OOTB
  • Don't need to use JSDOC comment for types

Test plan

  • Added unit tests and e2e tests
  • Green CI

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commit: 4f7105c

@ahnpnl ahnpnl force-pushed the feat/config-utils branch 3 times, most recently from 3496223 to 565fc14 Compare September 30, 2025 13:10
@ahnpnl ahnpnl marked this pull request as ready for review September 30, 2025 13:30
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ahnpnl commented Sep 30, 2025

Hi @cpojer @SimenB would you pls help me to check this PR? Thank you 🙏

ahnpnl added 2 commits October 9, 2025 20:10
@ahnpnl
feat(config): add defineConfig and mergeConfig functions
ae07875
@ahnpnl
docs(infra): simplify doc site start command
4f7105c 
To start Jest doc, we need to run `fetchSupporters` first otherwise it's not possible to start doc server
@ahnpnl ahnpnl force-pushed the feat/config-utils branch from 565fc14 to 4f7105c Compare October 9, 2025 18:10
@ahnpnl ahnpnl changed the title feat(config): add defineConfig and mergeConfig functions feat(jest-config): add defineConfig and mergeConfig functions Oct 9, 2025
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SimenB commented Oct 10, 2025

Yes, love this! I actually thought about this yesterday after seeing ESLint has added the same 👍

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SimenB approved these changes Oct 10, 2025
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thank you!

website/package.json
"scripts": {
"start": "docusaurus start",
"website:start": "yarn start",
"start": "yarn fetchSupporters && docusaurus start",
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do we need this?

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I noticed when doing a fresh checkout of Jest repo and start the documentation, doc server will fail because it needs to have supporters to be available on disk so dev server can pick up.

It took me some time to figure out this issue. Therefore adding this to start command would help

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