Fixed failure to apply a default language after a request with specified language

[bauerbrun0]

Description:

This pull request addresses the issue where the application, after a request with a specified language, fails to revert to a default language when the subsequent request does not specify a language. The current behavior retains the previous language instead of falling back to a default language, eg. the one set in initOptions.lng.

Changes Made:

1. Code Modification:

   • Updated the logic in onBeforeHandle; If a language is not detected and the new useLngAsDefault option is true, it falls back to the default language specified in initOptions.lng.

     // src/index.ts
     .onBeforeHandle(async ctx => {
         const detectedLanguage = await options.detectLanguage(ctx)
         if (detectedLanguage) {
             await _instance.changeLanguage(detectedLanguage)
             return
         }
     
         const { options: { lng }, language: currentLanguage } = _instance
     
         if (options.useLngAsDefault && lng && currentLanguage !== lng) {
             await _instance.changeLanguage(lng)
         }
     })

2. New Option:

   • Introduced a new option useLngAsDefault (defaults to true) to control whether the application should use the default language when a language is not specified/detected in a request.

     const app = new Elysia()
         .use(i18next({ instance, useLngAsDefault: true }))
         .get('/', ({ t }) => t('greeting'))

3. Test Cases:

   • Added a new test case to validate that the application falls back to the default language after a request with a specified language.
   • Added a test case to verify that opting out from using the default language (useLngAsDefault: false) works as intended.

4. Documentation:

   • Updated the README to include information about the new option useLngAsDefault.

Thank you for reviewing this pull request!

[eelkevdbos]

Hey! Sorry for the wait, I'll have a look at your contribution today. I have been messing around a bit with the language (detection) and the behaviour is not yet where I want it to be, but maybe this solves those issues.

[eelkevdbos]

The test case you have submitted is valid, thank you for that contribution!

I'd like to go for a slightly different solution to the one that you have implemented. To ensure complete isolation from other requests, I'd like to clone a fresh instance (with configured defaults) of the library on each request.

The rationale behind it is that I could see settings persist other than the current language and that would create a whole range of settings to make sure that the defaults are restored / used on subsequent requests.

Added benefit of cloning is that I am also eyeing the use of i18n in an async context, for example, rendering translations (for the currently set language) in jsx components (kitajs/html#31).

[morigs]

@eelkevdbos Do you still have plans on implementing this? Also, looking forward for #9

Please give me know if there a way to help

[eelkevdbos]

@eelkevdbos Do you still have plans on implementing this? Also, looking forward for #9

Please give me know if there a way to help

Sorry for the wait, I have a tentative implementation ready.