refactor: optimize theme script to prevent render-blocking (#601)

* refactor: optimize theme script to prevent render-blocking - Move theme script from `public/` to `src/scripts/` - Split into minimal inline script (FOUC prevention) + external script (non-blocking) - Rename `primaryColorScheme` to `initialColorScheme` - Rename `toggle-theme.js` to `theme.ts` - Use TypeScript for theme script - Update docs for theme customization
2026-08-14 11:29:33 +08:00 · 2026-01-10 07:26:25 +07:00
parent 25d25437cf
commit 5bb8e405bb
6 changed files with 182 additions and 103 deletions
@@ -130,10 +130,41 @@ const structuredData = {

    <ClientRouter />

-    <script is:inline src="/toggle-theme.js"></script>
+    <!-- Minimal inline script to prevent FOUC - sets theme immediately -->
+    <script is:inline>
+      (function () {
+        const initialColorScheme = ""; // "light" | "dark"
+        const currentTheme = localStorage.getItem("theme");
+
+        function getPreferTheme() {
+          if (currentTheme) return currentTheme;
+          if (initialColorScheme) return initialColorScheme;
+          return window.matchMedia("(prefers-color-scheme: dark)").matches
+            ? "dark"
+            : "light";
+        }
+
+        const themeValue = getPreferTheme();
+
+        // Set theme immediately to prevent flash
+        document.firstElementChild?.setAttribute("data-theme", themeValue);
+
+        // Export minimal API for external script
+        window.theme = {
+          themeValue: themeValue,
+          getTheme: () => window.theme.themeValue,
+          setTheme: val => {
+            window.theme.themeValue = val;
+          },
+        };
+      })();
+    </script>
  </head>
  <body>
    <slot />
+
+    <!-- Load full theme logic -->
+    <script src="../scripts/theme.ts"></script>
  </body>
 </html>