chore: initialize from frontend template 4dc033c

src/bootstrap/initialize-color-scheme.ts

@@ -0,0 +1,36 @@
+import {
+  normalizeColorSchemePreference,
+  resolveColorScheme,
+} from "../application/policies/color-scheme.ts";
+import type { ApplicationApi } from "../application/ports/in/application-api.ts";
+
+type ColorSchemeBrowser = Readonly<{
+  documentElement?: HTMLElement;
+  matchMedia?: (query: string) => Pick<MediaQueryList, "matches">;
+}>;
+
+/** Applies the persisted public preference before React paints. */
+export function initializeColorScheme(
+  preferences: Pick<ApplicationApi["preferences"], "getColorScheme">,
+  browser: ColorSchemeBrowser = {},
+) {
+  const documentElement = browser.documentElement ?? document.documentElement;
+  const matchMedia =
+    browser.matchMedia ??
+    (typeof window.matchMedia === "function"
+      ? window.matchMedia.bind(window)
+      : () => ({ matches: false }));
+  const preference = normalizeColorSchemePreference(
+    preferences.getColorScheme(),
+  );
+  const resolved = resolveColorScheme(
+    preference,
+    matchMedia("(prefers-color-scheme: dark)").matches,
+  );
+
+  documentElement.dataset.theme = resolved;
+  documentElement.dataset.themePreference = preference;
+  documentElement.style.colorScheme = resolved;
+
+  return Object.freeze({ preference, resolved });
+}