Chinese cannot be recognized using the browser language

[uubbbb]

Hello, the current mapbox language settings are: Simplified Chinese: zh-Hans, Traditional Chinese: zh-Hant, but in the browser, zh-Hans and zh-Hant are not recognized language codes, so there is no way to automatically display Chinese for users in Chinese areas.

The language codes recognized in the browser are:

Simplified Chinese: zh-cn, zh-sg, zh
Traditional Chinese: zh-tw, zh-hk

I hope it can be adjusted, thank you!

[1ec5]

This code is case-sensitive but should be case-insensitive:

mapbox-gl-language/index.js

Lines 145 to 150 in 95678e0

	const language = navigator.languages ? navigator.languages[0] : (navigator.language || navigator.userLanguage);
	const parts = language && language.split('-');
	let languageCode = language;
	if (parts.length > 1) {
	languageCode = parts[0];
	}

Moreover, this code only considers the language code in navigator.language, nothing else. According to the truncation fallback algorithm in RFC 4647, zh-Hant-TW should fall back to zh-Hant before zh. (Apple platforms such as macOS report navigator.language in the form zh-Hant-TW for Chinese.) But this code considers the preference to be just zh in the first place.

This issue is especially relevant if the supportedLanguages option includes zh-Hans or zh-Hant as supported languages, which is the default behavior:

mapbox-gl-language/index.js

Line 46 in 95678e0

this.supportedLanguages = options.supportedLanguages || ['ar', 'de', 'en', 'es', 'fr', 'it', 'ja', 'ko', 'mul', 'pt', 'ru', 'vi', 'zh-Hans', 'zh-Hant'];

[1ec5]

openstreetmap/iD#10911 (comment) demonstrates using the newish Locale.prototype.maximize to handle these and other language codes correctly without hardcoding fallback paths.