62 lines
1.7 KiB
TypeScript
62 lines
1.7 KiB
TypeScript
import { writable, type Writable } from 'svelte/store';
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export type SupportedLocale = 'de' | 'en';
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export const SUPPORTED_LOCALES: readonly SupportedLocale[] = ['de', 'en'] as const;
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const STORAGE_KEY = 'locale';
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interface Storage {
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getItem: (key: string) => string | null;
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setItem: (key: string, value: string) => void;
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}
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export interface DetectArgs {
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storage: Storage;
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navigatorLanguage: string | undefined;
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supported: readonly string[];
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}
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export function detectInitialLocale(args: DetectArgs): SupportedLocale {
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const stored = args.storage.getItem(STORAGE_KEY);
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if (stored && (args.supported as readonly string[]).includes(stored)) {
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return stored as SupportedLocale;
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}
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const nav = (args.navigatorLanguage ?? '').slice(0, 2).toLowerCase();
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if ((args.supported as readonly string[]).includes(nav)) {
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return nav as SupportedLocale;
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}
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return args.supported[0] as SupportedLocale;
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}
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function createActiveLocale(): Writable<SupportedLocale> & { bootstrap: () => void } {
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const store = writable<SupportedLocale>('de');
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let bootstrapped = false;
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function bootstrap() {
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if (bootstrapped) return;
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bootstrapped = true;
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if (typeof window === 'undefined') return;
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const initial = detectInitialLocale({
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storage: window.localStorage,
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navigatorLanguage: window.navigator.language,
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supported: SUPPORTED_LOCALES
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});
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store.set(initial);
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store.subscribe((v) => {
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try {
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window.localStorage.setItem(STORAGE_KEY, v);
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} catch {
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// private-mode / quota — ignorieren
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}
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});
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}
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return {
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subscribe: store.subscribe,
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set: store.set,
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update: store.update,
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bootstrap
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};
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}
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export const activeLocale = createActiveLocale();
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