immich/web/src/lib/stores/preferences.store.ts

import { browser } from '$app/environment';
import { persisted } from 'svelte-local-storage-store';

const initialTheme =
	browser && !window.matchMedia('(prefers-color-scheme: dark)').matches ? 'light' : 'dark';

// The 'color-theme' key is also used by app.html to prevent FOUC on page load.
export const colorTheme = persisted<'dark' | 'light'>('color-theme', initialTheme, {
	serializer: {
		parse: (text) => (text === 'light' ? text : 'dark'),
		stringify: (obj) => obj
	}
});

// Locale to use for formatting dates, numbers, etc.
export const locale = persisted<string | undefined>('locale', undefined, {
	serializer: {
		parse: (text) => text,
		stringify: (obj) => obj ?? ''
	}
});