Add an option like singleDetect

[NotEvenANeko]

🚀 Feature Proposal

Add an option like singleDetect which only detect one language code instead of multiple codes. Like detect method from @lingui/detect-locale.

Motivation

Current detection order will return multiple language codes, like order: ['querystring', 'navigator'] will return [...codesFromQueryString, ...codesFromNavigator]. But I want something can return only one code or only codesFromQueryString.

Assume we need to support ['ja', 'zh-CN', 'zh-HK', 'en'], I set supportedLngs to this array to support fallback between zh-CN and zh-HK. But when user sets the querystring to ja-JP and navigator.languages returns ['en'], it matches en in the supportedLngs, not ja.

Example

// url: example.com/?lang=ja-JP
// navigator.languages -> ["en"]
i18n.use(LanguageDetector).init({
  resources,
  fallbackLng: ["en"],
  supportedLngs: ["ja", "zh-CN", "zh-HK", "en"],
  interpolation: {
    escapeValue: false
  },
  detection: {
    order: ["querystring", "navigator"],
    lookupQuerystring: "lang",
    caches: [],
    singleDetect: true, // detect only one code or only result from querystring
  }
});

console.log(i18n.languages); // should be ["ja", "en"/* fallback en */], not ["en"/* getBestMatchFromCodes, because detect() returns ["ja-JP", "en"] now */]

[jamuhl]

ja-JP is not in your supportedLngs list....therefore it gets rejected resulting in en only

use option nonExplicitSupportedLngs: true to allow ja-JP if ja is in the list https://www.i18next.com/overview/configuration-options#languages-namespaces-resources

[stale[bot]]

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