Fallback bug

[xareelee]

I forward this issue from AlexanderZaytsev/react-native-i18n#96 (comment).

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The fallback strategy has a bug. The Chinese mandarin language (zh/中, how to pronounce) use a character system (Han/漢, how to write) which is divided into two kinds of symbol styles: Traditional Chinese characters (zh-Hant, where t stands for Traditional) and Simplified Chinese characters (zh-Hans, where s stands for Simplified).

For example, a user uses Traditional Chinese characters and lives in Taiwan, his language and locale should be zh-Hant-TW, and the priority of the i18n fallback strategy should be:

1. zh-Hant-TW: Traditional Chinese characters used in Taiwan
2. zh-Hant: general Traditional Chinese characters
3. zh: general Chinese characters

The current fallback strategy of i18n-js has a bug. If it doesn't find zh-Hant-TW, it will only look for zh, not zh-Hant first.

I want to provide zh-Hant for all Traditional Chinese and zh-Hans for all Simplified Chinese no matter what the locale is, but it can't currently work. Devices provide lang+locale and i18n-js fallbacks to zh directly in this scenario.

Fallback strategy:

• Expected: zh-Hant-TW -> zh-Hant -> zh -> default language
• Current: zh-Hant-TW -> zh -> default language

// general Chinese
zh

// Traditional Chinese 
zh-Hant

// Simplified Chinese
zh-Hans

// Traditional Chinese + Locale
zh-Hant-TW
zh-Hant-SG
zh-Hant-HK
zh-Hant-CN

// Simplified Chinese + Locale
zh-Hans-TW
zh-Hans-SG
zh-Hans-HK
zh-Hans-CN

[PikachuEXE]

Do you know how ruby's i18n works for this case?
I guess the fallback logic is from ruby.
If it handles that already, we can try to copy from that.
If not let's think about a way to make your case work.

[xareelee]

@PikachuEXE, I have no idea.

I reported this issue because I'm using react-native-i18n which depends on this library and I encountered this issue.

I'm not sure whether anyone else encountered this issue in i18n-js too.

I want to provide zh-hant and zh-hans for Traditional and Simplified Chinese in all locales, respectively, not to provide zh for all general Chinese.

[PikachuEXE]

OK let me check the logic from Ruby's I18n and see how it handle this case
Maybe we can copy the logic it :P

Let me get back to you later

[nerdmed]

@xareelee @PikachuEXE thanks a lot. Same here i am also using it with react-native-i18n and for me it does not work even though we just want to support the simplified chinese "zh-Hans". Would be awesome to fix the logic here.

See: AlexanderZaytsev/react-native-i18n#93 (comment)

[flexsurfer]

https://github.com/fnando/i18n-js/blob/master/app/assets/javascripts/i18n.js#L273 here it takes only first element "zh" from 3 elements ["zh","hans","tw"], logic here should be changed, it should add "zh" and "zh-hans".

[nerdmed]

yes. i think there is a more semantic way to achieve what is done there. Anyone here that is interested and has already worked with this lib? I think it makes sense to improve this part with a PR?

[PikachuEXE]

Please take a look at #465 to see if it works