feat(core): add i18n.setCatalogAndActivate for easier nextjs integration

[timofei-iatsenko]

Description

Fixes #1339

Integration with nextjs is not easy as it could be. You can check how much non-trivial code should be written https://github.com/lingui/swc-plugin/pull/38/files to make it work without accessing private properties of i18n.

This PR brings special method which

• set all data in one call. More aligned with how users really use it now.
• allow to set notify: false which is crucial to make integration easy.

The problem is in the race condition. When you setting locale or messages i18n emits an event. For that moment of time LinguiProvider already initialized and subscribed to the event from i18n. The emitting of this event happened inside react's "reconciliation phase" and it causes another setState() inside LinguiProvider which is not allowed during this phase.

Simply disabling emitting event in this method fixes the issue and simplify integration a lot.

So instead

export function useLinguiInit(messages: Messages) {
  const router = useRouter()
  const locale = router.locale || router.defaultLocale!
  const firstRender = useRef(true)

  // run only once on the first render (for server side)
  if (messages && firstRender.current) {
    i18n.load(locale, messages)
    i18n.activate(locale)
    firstRender.current = false
  }

  useEffect(() => {
    if (messages) {
      i18n.load(locale, messages)
      i18n.activate(locale)
    }
  }, [locale, messages])

  return i18n;
}

User have to write:

export function useLinguiInit(messages: Messages) {
  const router = useRouter()
  const locale = router.locale || router.defaultLocale!
  i18n.loadAndActivate(locale, messages, false);

  return i18n;
}

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

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 necessary documentation (if appropriate)

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Name	Status	Preview	Comments	Updated
js-lingui	✅ Ready (Inspect)	Visit Preview	💬 Add your feedback	Mar 21, 2023 at 10:39AM (UTC)

[github-actions]

size-limit report 📦

Path	Size
./packages/core/build/esm/index.js	1.57 KB (0%)
./packages/detect-locale/build/esm/index.js	812 B (0%)
./packages/react/build/esm/index.js	1.59 KB (0%)
./packages/remote-loader/build/esm/index.js	7.25 KB (0%)

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: +0.16 🎉

Comparison is base (10633f3) 75.17% compared to head (bd20146) 75.34%.

Additional details and impacted files

@@            Coverage Diff             @@
##             next    #1541      +/-   ##
==========================================
+ Coverage   75.17%   75.34%   +0.16%     
==========================================
  Files          78       78              
  Lines        1962     1971       +9     
  Branches      512      515       +3     
==========================================
+ Hits         1475     1485      +10     
+ Misses        376      375       -1     
  Partials      111      111              

Impacted Files	Coverage Δ
packages/core/src/i18n.ts	66.66% <100.00%> (+7.01%)	⬆️

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[vonovak]

hello 👋
quick questions:

1. why is this doing this: this._messages[this._locale] = messages as opposed to running this._load(this_locale, messages)? The docs say "This method is i18n.load() + i18n.activate() in one pass." but that's not 100% true in fact. I'd say the code should stay but the docs should be more accurate?

2. if the "change" event is not emitted, how does the integration with the I18nProvider work?

   js-lingui/packages/react/src/I18nProvider.tsx

   Line 63 in 3659dec

   const updateContext = () => {

thanks :)

[timofei-iatsenko]

@vonovak look at changes in this integration in nextjs https://github.com/lingui/swc-plugin/pull/38/files

why is this doing this: this._messages[this._locale] = messages as opposed to running this._load(this_locale, messages)? The docs say "This method is i18n.load() + i18n.activate() in one pass." but that's not 100% true in fact. I'd say the code should stay but the docs should be more accurate?

i did not get the question