Xiaohan-Tian
49 lines
1.7 KiB
TypeScript
49 lines
1.7 KiB
TypeScript
import type { LanguageSetting, ResolvedLocaleCode } from './types';
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const CHINESE_LANGUAGE_PREFIX = 'zh';
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const DEFAULT_LOCALE: ResolvedLocaleCode = 'en_us';
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// BCP 47 subtags that indicate Traditional Chinese (Hant script or HK/TW/MO regions)
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const TRADITIONAL_CHINESE_SUBTAGS = new Set(['hk', 'tw', 'mo', 'hant']);
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export function normalizeLanguageSetting(value: unknown): LanguageSetting {
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return value === 'zh_cn' || value === 'en_us' || value === 'zh_hk' || value === 'auto' ? value : 'auto';
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}
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export function getBrowserLocales(): string[] {
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if (typeof navigator === 'undefined') {
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return [];
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}
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if (Array.isArray(navigator.languages) && navigator.languages.length > 0) {
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return navigator.languages.filter((value): value is string => typeof value === 'string' && value.length > 0);
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}
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return typeof navigator.language === 'string' && navigator.language.length > 0
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? [navigator.language]
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: [];
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}
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export function resolveLanguageSetting(
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setting: LanguageSetting,
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browserLocales: string[] = getBrowserLocales(),
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): ResolvedLocaleCode {
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if (setting === 'en_us' || setting === 'zh_cn' || setting === 'zh_hk') {
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return setting;
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}
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for (const locale of browserLocales) {
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const normalizedLocale = locale.trim().toLowerCase();
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if (normalizedLocale === CHINESE_LANGUAGE_PREFIX) {
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return 'zh_cn';
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}
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if (normalizedLocale.startsWith(`${CHINESE_LANGUAGE_PREFIX}-`)) {
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const subtags = normalizedLocale.slice(CHINESE_LANGUAGE_PREFIX.length + 1).split('-');
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const isTraditional = subtags.some((tag) => TRADITIONAL_CHINESE_SUBTAGS.has(tag));
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return isTraditional ? 'zh_hk' : 'zh_cn';
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}
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}
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return DEFAULT_LOCALE;
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}
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