[feymo]

Q	A
Bug fix?	yes
New feature?	yes
Deprecations?	no
Documentation?	yes
Issues
License	MIT

Follow-up of #4076 , which did the same for UX Router.

The translator reads its locale from <html data-symfony-ux-translator-locale> or <html lang>. When both are missing, it falls back to a hard-coded en. The bundle does not dump the application default locale, so the JavaScript side cannot know it. With framework.default_locale: fr and a layout without lang, messages are translated in English.

The dumped index.js file now exports the kernel.default_locale parameter as defaultLocale, and index.d.ts declares it when TypeScript types are dumped. createTranslator() accepts it as a new defaultLocale option:

import { createTranslator } from '@symfony/ux-translator';
import { messages, localeFallbacks, defaultLocale } from '../var/translations/index.js';

export const { trans } = createTranslator({ messages, localeFallbacks, defaultLocale });

The locale is resolved in this order: the locale option, <html data-symfony-ux-translator-locale>, <html lang>, the defaultLocale option, then en. A translator.js file without the option keeps its current behavior, and getDefaultLocale() is unchanged.

default_locale: fr, no lang attribute	Before	After
getLocale() in the browser	en	fr
getLocale() without document (SSR)	ReferenceError: document is not defined	fr

This PR also fixes two bugs on the way:

• Without document (server-side rendering, tests in Node), createTranslator() threw a ReferenceError. It now skips the page attributes, which is also what makes the new option useful there.
• Locales with a script and a region were only partly converted, because replace() only replaces the first match. <html lang="zh-Hant-TW"> gave zh_Hant-TW, which matches no catalogue, and an ICU message in zh_Hant_TW threw RangeError: Incorrect locale information provided. Both conversions now use replaceAll().

The Flex recipe needs a new 3.7 version that passes defaultLocale. I will open it on symfony/recipes once this is merged.

[Kocal]

For 3.7

[github-actions]

📊 Packages dist files size difference

Thanks for the PR! Here is the difference in size of the packages dist files between the base branch and the PR.
Please review the changes and make sure they are expected.

File	Before (Size / Gzip)	After (Size / Gzip)
Translator
translator_controller.d.ts	1.87 kB / 669 B	1.91 kB+2% 📈 / 678 B+1% 📈
translator_controller.js	7.39 kB / 2.29 kB	7.54 kB+2% 📈 / 2.33 kB+2% 📈

[Kocal]

Thank you @feymo.