fix: screen should not flash in the dark mode

index.typ

@@ -7,7 +7,7 @@
 #show: load-html-template.with(
   "/typ/templates/template.html",
   extra-head: {
-    vite.load-files(("src/main.ts",))
+    vite.load-files(("src/main.ts", "src/theme.ts#nomodule"))
   },
 )
 

src/main.ts

@@ -2,6 +2,4 @@ import "./global.css";
 import "./show-example.css";
 import "./util.css";
 
-import "./theme.ts";
-
 import "./respec/mod.ts";

src/theme.ts

@@ -1,41 +1,68 @@
-type Theme = 'auto' | 'light' | 'dark';
+/**
+ * Theme toggle.
+ *
+ * This script should be executed before DOM is loaded.
+ * Otherwise, the screen will flash in the dark mode.
+ */
 
-const themeToggle = document.getElementById("theme-toggle") as HTMLElement;
-const themeSelections: HTMLDivElement[] = Array.from(themeToggle.querySelectorAll('div.theme-icon'));
+type Theme = "auto" | "light" | "dark";
 
-// Load saved theme preference or default to auto (sync system)
-if (typeof localStorage !== "undefined") {
-  const theme = localStorage.getItem("theme") ?? 'auto';
-  applyTheme(theme as Theme);
-}
-
-// Theme toggle functionality
-themeToggle.addEventListener("click", () => {
-  const current = themeSelections.findIndex(icon => !icon.hidden);
-  const next = themeSelections[(current + 1) % themeSelections.length].classList;
-  const theme = next.contains("auto") ? "auto" : next.contains("light") ? "light" : "dark";
-  applyTheme(theme);
-});
-
-function applyTheme(theme: Theme): void {
+/** Same as `applyTheme`, but works before DOM is loaded */
+function applyThemeWithoutDOM(theme: Theme): void {
   // Change the page’s theme
-  const resolved = theme === 'auto' ? getSystemTheme() : theme;
+  const resolved = theme === "auto" ? getSystemTheme() : theme;
   if (resolved === "dark") {
     document.documentElement.classList.add("dark");
   } else {
     document.documentElement.classList.remove("dark");
   }
+}
 
-  // Update theme selections
-  themeSelections.forEach(icon => {
-    icon.hidden = !icon.classList.contains(theme);
+// Load saved theme preference or default to auto (sync system)
+if (typeof localStorage !== "undefined") {
+  const theme = localStorage.getItem("theme") ?? "auto";
+  applyThemeWithoutDOM(theme as Theme);
+}
+
+document.addEventListener("DOMContentLoaded", () => {
+  const themeToggle = document.getElementById("theme-toggle") as HTMLElement;
+  const themeSelections: HTMLDivElement[] = Array.from(
+    themeToggle.querySelectorAll("div.theme-icon"),
+  );
+
+  // Load saved theme preference or default to auto (sync system)
+  if (typeof localStorage !== "undefined") {
+    const theme = localStorage.getItem("theme") ?? "auto";
+    applyTheme(theme as Theme);
+  }
+
+  // Theme toggle functionality
+  themeToggle.addEventListener("click", () => {
+    const current = themeSelections.findIndex((icon) => !icon.hidden);
+    const next =
+      themeSelections[(current + 1) % themeSelections.length].classList;
+    const theme = next.contains("auto")
+      ? "auto"
+      : next.contains("light")
+      ? "light"
+      : "dark";
+    applyTheme(theme);
   });
 
-  // Save for future loads
-  localStorage.setItem("theme", theme);
-}
+  function applyTheme(theme: Theme): void {
+    applyThemeWithoutDOM(theme);
+
+    // Update theme selections
+    themeSelections.forEach((icon) => {
+      icon.hidden = !icon.classList.contains(theme);
+    });
+
+    // Save for future loads
+    localStorage.setItem("theme", theme);
+  }
+});
 
-function getSystemTheme(): 'dark' | 'light' {
+function getSystemTheme(): "dark" | "light" {
   const match = window.matchMedia &&
     window.matchMedia("(prefers-color-scheme: dark)").matches;
   return match ? "dark" : "light";

typ/packages/vite.typ

@@ -6,28 +6,46 @@
 
 #let manifest-path = "/dist/.vite/manifest.json"
 
+/// - raw-path (str):
+/// -> (path: str, as-module: bool)
+#let _parse-path(raw-path) = {
+  if raw-path.ends-with("#nomodule") {
+    (path: raw-path.trim("#nomodule", at: end), as-module: false)
+  } else {
+    (path: raw-path, as-module: true)
+  }
+}
+
 /// Load a file
 ///
-/// - paths (array<str>):
-/// - mode ("dev" | "prod"):
+/// All scripts will be loaded as a module be default.
+///
+/// If a script should be executed before DOM is loaded, add a `#nomodule` suffix.
+/// Note that it is not officially supported by vite, and does not work in `dev` mode.
+///
+/// - paths (array<str>): Path to typescript entry points.
 /// -> content
 #let load-files(paths) = {
   let url(path) = asset-url("/" + path)
 
   if mode == "dev" {
     h.script({ }, type: "module", src: url("@vite/client"))
-    for path in paths {
+    for raw-path in paths {
+      let (path, as-module) = _parse-path(raw-path)
       h.script({ }, type: "module", src: url(path))
     }
   } else {
     let manifest = json(manifest-path)
 
-    for chunk in manifest.values() {
+    for raw-path in paths {
+      let (path, as-module) = _parse-path(raw-path)
+      let chunk = manifest.at(path)
+
       assert("imports" not in chunk, message: "the `imports` field is not supported yet")
 
-      h.script({ }, type: "module", src: url(chunk.file))
+      h.script({ }, src: url(chunk.file), ..if as-module { (type: "module") })
 
-      for css in chunk.css {
+      for css in chunk.at("css", default: ()) {
         h.link({ }, rel: "stylesheet", href: url(css))
       }
     }

vite.config.ts

@@ -11,6 +11,7 @@ export default defineConfig({
     rollupOptions: {
       input: {
         main: resolve(__dirname, "src/main.ts"),
+        theme: resolve(__dirname, "src/theme.ts"),
       },
     },
     manifest: true, // https://vite.dev/guide/backend-integration.html