feat!: ESM-only conversion by timofei-iatsenko · Pull Request #2368 · lingui/js-lingui

timofei-iatsenko · 2025-11-20T09:03:48Z

Description

#2363

Most noticable changes:

Packages migrated to ESM-only, except @lingui/babel-plugin-lingui-macro, @lingui/loader, @lingui/macro (deprecated). Those excluded packages still using ESM depdendecies, so it will affect theirs consumers. Those packages was not converted to esm because there is no sense in that, babel and webpack consume them using a require function.
Jest replaced to Vitest. I wasn't able to make Jest working with ESM modules without hacks. Vitest just worked out of the box with no issue
Every package now has it's own tsconfig and build pipeline, since packages has diffrent targets (one for nodejs without a bundler, other for a bundler)
The monorepo layout changed from using typescript path aliases to consume built artifacts. This is consequence of the point above. That ruined the whole dx inside of the monorepo, but this is temporarly step to make it work first, in next iterations i will try to improve development experience.

Types of changes

Bugfix (non-breaking change which fixes an issue)
New feature (non-breaking change which adds functionality)
Breaking change (fix or feature that would cause existing functionality to not work as expected)
Documentation update
Examples update

Fixes # (issue)

Checklist

I have read the CONTRIBUTING and CODE_OF_CONDUCT docs
I have added tests that prove my fix is effective or that my feature works
I have added the necessary documentation (if appropriate)

vercel · 2025-11-20T09:03:53Z

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timofei-iatsenko · 2026-01-15T16:12:19Z

@andrii-bodnar let's agree on the strategy for the new version for this.

As i mentioned this change is enough for version V6. However i'm going to prepare few more changes with restructuring which would be good to merge as a separate PR and stop this one growing.

We can resurrect a next branch, merge PR into it. Wait for more upcoming PRs. Then release V6 from the next branch.
We can merge that directly into main, wait for few more PRs and release V6 directly from the main.

In any case it's better to merge and release whatever non-breaking opened pull request we have and than put a code freeze on main branch until v6 would be released.

andrii-bodnar · 2026-01-15T16:21:29Z

@timofei-iatsenko let's use the same workflow with the next branch. This will allow us to prepare everything (blog post, pre-releases, etc.) without blocking us from any stable release in the meantime.

I just pushed a fresh next branch created from the latest main

timofei-iatsenko · 2026-01-16T11:25:49Z

@andrii-bodnar could you sync next branch once again? Also isn't this workflow helpful https://github.com/lingui/js-lingui/actions/workflows/next-sync.yml

codecov · 2026-01-16T11:32:59Z

Codecov Report

❌ Patch coverage is 80.26316% with 30 lines in your changes missing coverage. Please review.
✅ Project coverage is 87.23%. Comparing base (dd43fb0) to head (9f396c9).
⚠️ Report is 281 commits behind head on next.

Files with missing lines	Patch %	Lines
packages/cli/src/lingui-extract.ts	46.15%	7 Missing ⚠️
packages/cli/src/workers/compileWorker.ts	0.00%	3 Missing and 1 partial ⚠️
...-experimental/workers/extractWorkerWrapper.prod.ts	0.00%	2 Missing and 1 partial ⚠️
...kages/cli/src/workers/compileWorkerWrapper.prod.ts	0.00%	2 Missing and 1 partial ⚠️
...kages/cli/src/workers/extractWorkerWrapper.prod.ts	0.00%	2 Missing and 1 partial ⚠️
.../src/extract-experimental/workers/extractWorker.ts	0.00%	2 Missing ⚠️
packages/cli/src/workers/extractWorker.ts	0.00%	2 Missing ⚠️
...ackages/babel-plugin-extract-messages/src/index.ts	90.90%	1 Missing ⚠️
packages/cli/api.ts	0.00%	0 Missing and 1 partial ⚠️
packages/cli/src/api/extractWorkerPool.ts	90.90%	1 Missing ⚠️
... and 3 more

Additional details and impacted files

@@             Coverage Diff             @@
##             next    #2368       +/-   ##
===========================================
+ Coverage   76.66%   87.23%   +10.56%     
===========================================
  Files          81      123       +42     
  Lines        2083     7254     +5171     
  Branches      532     1494      +962     
===========================================
+ Hits         1597     6328     +4731     
- Misses        375      907      +532     
+ Partials      111       19       -92

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andrii-bodnar · 2026-01-16T12:57:10Z

@timofei-iatsenko yes, this workflow has been explicitly disabled, I will enable it

# Conflicts: # babel.config.js # jest.config.js # packages/cli/package.json # packages/cli/src/lingui-extract.ts # packages/cli/src/services/translationIO.ts # packages/extractor-vue/package.json # packages/loader/package.json # packages/message-utils/package.json # packages/message-utils/src/generateMessageId.test.ts # packages/metro-transformer/package.json # packages/react/tsconfig.json # yarn.lock

timofei-iatsenko · 2026-01-24T11:09:43Z

This one is ready to be merged, - still not ready for release - i will fixup in separate PRs

timofei-iatsenko · 2026-01-24T11:10:53Z

I merged recent changes from main, but target for pr is next, that's why it shows unrelated changes. It should be good once next would be synced with main.

yslpn · 2026-01-24T14:36:20Z

package.json

-  "packageManager": "yarn@3.4.1"
+  "packageManager": "yarn@3.4.1",
+  "resolutions": {
+    "threads@^1.7.0": "patch:threads@npm%3A1.7.0#./.yarn/patches/threads-npm-1.7.0-c432dbb3e9.patch"


You've done a great job, thank you very much!

Have you considered switching to a different threading library instead of patching the current dependency? Perhaps it's worth creating a separate issue for this. I briefly looked at tinypool, for example, which is used in the vitest library: https://github.com/tinylibs/tinypool

Yes, i considered. I tried priscina - but feel it very low level and API is quite diverged from the threads used. This patching would not work when the library would be consumed by the users, so i defenetily should tackle that.

This patch here is a temporal fix to mitigate issue and unblock further migration to ESM.

I will defentely take a look at tinypool as well.

UPD, i just recalled to myself what was patched here, and it's type only, so it most likely should not affect end users, until they would use cli api directly without skipLibCheck: true. However, the threads library looks unmaintained, and if you @yslpn want to experiment and change the implementation to tinypool i wouldn't resist. Only one request from me - make it after esm would be merged to avoid conflicts and try to keep the same level of the typesafety between workers implementation / and invocation.

timofei-iatsenko · 2026-01-26T08:45:23Z

I merged recent changes from main, but target for pr is next, that's why it shows unrelated changes. It should be good once next would be synced with main.

I messed up the git. The same commits after merge in next and main essentially a different entities, so my branch is not showing correct diff right now and the whole history is messed up.

@andrii-bodnar could you drop the next branch entirely and recreate if from scratch. so there is no merge commits on it.

andrii-bodnar · 2026-01-26T08:54:11Z

@timofei-iatsenko done

timofei-iatsenko · 2026-01-26T09:00:08Z

@andrii-bodnar thanks, now it's good to be merged. Once it merged it should be code-freeze on the main branch.

.github/workflows/main-suite.yml

examples/vite-project-react-babel/package.json

package.json

vercel · 2026-01-26T14:37:03Z

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Project	Deployment	Review	Updated (UTC)
js-lingui	Ready	Preview	Jan 26, 2026 2:37pm

Co-authored-by: Andrii Bodnar <andrii.bodnar@crowdin.com>

timofei-iatsenko added 28 commits November 11, 2025 11:58

convert cli to esm imports

0bedb56

apply path for threads

606b394

implement vitest for cli, convert to esm

d576105

replace require.main usages

1a334b1

rewrite formatter-po to esm

58fef05

rewrite conf to esm

5a8d474

rewrite babel-plugin-lingui-macro to commonjs only

baa7492

esm only for vite plugin

f36cd9d

migrate core

83256cb

migrate react package

4c6ec1a

migrate po-gettext package

936c257

migrate message-utils package

ea34389

migrate format-csv package

4a6785c

migrate format-json package

4d15a76

remove stub functionality

f55467d

remove tsconfig path aliases

39d64b9

migrate extractor-vue

912d4ff

migrate metro transformer

4bee4eb

migrate loader

1de6646

migrate babel-plugin-extract-messages

565731c

fixes

d85986f

migrate detect locale

2521533

migrate jest-mocks

86385f2

mskip remote loader tests

8db47b6

fix tests

d814ed8

vitest plugin test fixes

57b3d98

setup coverage

622cc1a

delete jest test runner

dbe07fc

Merge branch 'main' into esm

501253a

remove outdated test

b5d7546

remove outdated test

11a99f0

timofei-iatsenko changed the base branch from main to next January 15, 2026 16:22

fix

349db49

andrii-bodnar added the v6 label Jan 16, 2026

timofei-iatsenko added 2 commits January 24, 2026 11:45

migrate changes merged from main

4ecdb5f

timofei-iatsenko marked this pull request as ready for review January 24, 2026 11:09

timofei-iatsenko mentioned this pull request Jan 24, 2026

V6 Roadmap: ESM Only distribution #2363

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yslpn reviewed Jan 24, 2026

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timofei-iatsenko requested a review from andrii-bodnar January 26, 2026 13:38

timofei-iatsenko mentioned this pull request Jan 26, 2026

refactor!: strictNullChecks for cli lib packages #2412

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andrii-bodnar reviewed Jan 26, 2026

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Co-authored-by: Andrii Bodnar <andrii.bodnar@crowdin.com>

andrii-bodnar approved these changes Jan 26, 2026

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andrii-bodnar merged commit d2a8e96 into lingui:next Jan 26, 2026
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timofei-iatsenko deleted the esm branch January 27, 2026 08:31

andrii-bodnar added this to the v6 milestone Jan 29, 2026

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