Separate theme management from theme component

src/lib/theme.ts

@@ -0,0 +1,42 @@
+import { writable, type Writable } from '@square/svelte-store';
+import { appWindow, type Theme } from '@tauri-apps/api/window';
+
+const themeStorageKey = 'theme';
+export const theme: Writable<string> = writable('dark');
+
+let systemTheme: string | null;
+
+export function initTheme() {
+	appWindow.theme().then((value: Theme | null) => {
+		systemTheme = value;
+		updateDom();
+	});
+	appWindow.onThemeChanged((e) => {
+		systemTheme = e.payload;
+		updateDom();
+	});
+}
+
+export function setTheme(name: string) {
+	localStorage.setItem(themeStorageKey, name);
+	theme.set(name);
+	updateDom();
+}
+
+export function getTheme(): string | null {
+	return localStorage.getItem(themeStorageKey);
+}
+
+export function updateDom() {
+	const docEl = document.documentElement;
+	const selectedTheme = localStorage.getItem(themeStorageKey);
+	if (selectedTheme == 'dark' || (selectedTheme == 'system' && systemTheme == 'dark')) {
+		docEl.classList.add('dark');
+		docEl.style.colorScheme = 'dark';
+		theme.set('dark');
+	} else if (selectedTheme == 'light' || (selectedTheme == 'system' && systemTheme == 'light')) {
+		docEl.classList.remove('dark');
+		docEl.style.colorScheme = 'light';
+		theme.set('light');
+	}
+}

src/routes/+layout.ts

@@ -3,6 +3,7 @@ import { api, log } from '$lib';
 import Posthog from '$lib/posthog';
 import Sentry from '$lib/sentry';
 import { wrapLoadWithSentry } from '@sentry/sveltekit';
+import { initTheme } from '$lib/theme';
 
 export const ssr = false;
 export const prerender = true;
@@ -10,6 +11,7 @@ export const csr = true;
 
 export const load: LayoutLoad = wrapLoadWithSentry(({ fetch }) => {
 	log.setup();
+	initTheme();
 	return {
 		projects: api.projects.Projects(),
 		cloud: api.CloudApi({ fetch }),

src/routes/ThemeSelector.svelte

@@ -1,43 +1,15 @@
 <script lang="ts">
-	import { appWindow, type Theme } from '@tauri-apps/api/window';
-
-	const themeStorageKey = 'theme';
-	let systemTheme: string | null;
-	let selectedTheme: string | null;
-
-	appWindow.theme().then((value: Theme | null) => {
-		selectedTheme = localStorage.getItem(themeStorageKey);
-		systemTheme = value;
-		updateDom();
-	});
-	appWindow.onThemeChanged((e) => {
-		systemTheme = e.payload;
-		updateDom();
-	});
+	import { theme, setTheme } from '$lib/theme';
 
 	function onThemeChange(e: Event & { currentTarget: HTMLSelectElement }) {
-		selectedTheme = e.currentTarget.value;
-		localStorage.setItem(themeStorageKey, selectedTheme);
-		updateDom();
-	}
-
-	function updateDom() {
-		const docEl = document.documentElement;
-		if (selectedTheme == 'dark' || (selectedTheme == 'system' && systemTheme == 'dark')) {
-			docEl.classList.add('dark');
-			docEl.style.colorScheme = 'dark';
-		} else if (selectedTheme == 'light' || (selectedTheme == 'system' && systemTheme == 'light')) {
-			docEl.classList.remove('dark');
-			docEl.style.colorScheme = 'light';
-		}
+		setTheme(e.currentTarget.value);
 	}
 </script>
 
 <div>
-	<label for="dark-mode-toggle" class="mr-2">Theme</label>
-	<select bind:value={selectedTheme} on:change={onThemeChange}>
-		<option>system</option>
-		<option>light</option>
-		<option>dark</option>
+	<select bind:value={$theme} on:change={onThemeChange}>
+		<option value="system">System preference</option>
+		<option value="light">Light</option>
+		<option value="dark">Dark</option>
 	</select>
 </div>