🐛 fix: properly initialise currentTheme

The `currentTheme` variable is now properly initialized when setting
the initial theme, which fixes the "extra click" issue observed when system preference
is `dark` and there's no saved theme in localStorage.

Also minifies the themeSwitcher.

Fixes #94

static/js/themeSwitcher.js

@@ -1,33 +1,37 @@
 // Get the theme switcher button element.
 const themeSwitcher = document.querySelector(".theme-switcher");
 
-// Retrieve theme from localStorage.
-let currentTheme = localStorage.getItem("theme");
+// Retrieve theme from either the localStorage or the data-theme attribute on the document element.
+let currentTheme = localStorage.getItem("theme") || document.documentElement.getAttribute('data-theme');
 
-// Function to switch between dark and light themes.
-function setTheme(theme) {
+// Function to set theme
+function setTheme(theme, saveToLocalStorage = false) {
     document.documentElement.setAttribute("data-theme", theme);
-    localStorage.setItem("theme", theme);
+    currentTheme = theme;
+
+    if (saveToLocalStorage) {
+        localStorage.setItem("theme", theme);
+    }
 
-    // Dispatch a custom event for comment systems.
+    // Dispatch a custom event for utterances and giscus.
     const event = new CustomEvent("themeChanged", {
         detail: { theme: theme }
     });
     window.dispatchEvent(event);
 }
 
+// Function to switch between dark and light themes.
 function switchTheme() {
     // Set the new theme based on the current theme.
     const newTheme = currentTheme === "dark" ? "light" : "dark";
-    setTheme(newTheme);
+    setTheme(newTheme, true); // Save the theme to localStorage when the user changes it.
 }
 
+// Initialize the theme switcher button.
 themeSwitcher.addEventListener("click", switchTheme, false);
 
 // Update the theme based on system preference if the user hasn't manually changed the theme.
 window.matchMedia("(prefers-color-scheme: dark)").addEventListener("change", e => {
-    if (!localStorage.getItem("theme")) {
-        const newTheme = e.matches ? "dark" : "light";
-        setTheme(newTheme);
-    }
+    const newTheme = e.matches ? "dark" : "light";
+    setTheme(newTheme);
 });