refactor theme toggle; add delegate-it

assets/js/delegate-it.js

@@ -0,0 +1,90 @@
+(function() {
+
+/** Keeps track of raw listeners added to the base elements to avoid duplication */
+const ledger = new WeakMap();
+function editLedger(wanted, baseElement, callback, setup) {
+    var _a, _b;
+    if (!wanted && !ledger.has(baseElement)) {
+        return false;
+    }
+    const elementMap = (_a = ledger.get(baseElement)) !== null && _a !== void 0 ? _a : new WeakMap();
+    ledger.set(baseElement, elementMap);
+    if (!wanted && !ledger.has(baseElement)) {
+        return false;
+    }
+    const setups = (_b = elementMap.get(callback)) !== null && _b !== void 0 ? _b : new Set();
+    elementMap.set(callback, setups);
+    const existed = setups.has(setup);
+    if (wanted) {
+        setups.add(setup);
+    }
+    else {
+        setups.delete(setup);
+    }
+    return existed && wanted;
+}
+function isEventTarget(elements) {
+    return typeof elements.addEventListener === 'function';
+}
+function safeClosest(event, selector) {
+    let target = event.target;
+    if (target instanceof Text) {
+        target = target.parentElement;
+    }
+    if (target instanceof Element && event.currentTarget instanceof Element) {
+        // `.closest()` may match ancestors of `currentTarget` but we only need its children
+        const closest = target.closest(selector);
+        if (closest && event.currentTarget.contains(closest)) {
+            return closest;
+        }
+    }
+}
+// This type isn't exported as a declaration, so it needs to be duplicated above
+function delegate(base, selector, type, callback, options) {
+    // Handle Selector-based usage
+    if (typeof base === 'string') {
+        base = document.querySelectorAll(base);
+    }
+    // Handle Array-like based usage
+    if (!isEventTarget(base)) {
+        const subscriptions = Array.prototype.map.call(base, (element) => delegate(element, selector, type, callback, options));
+        return {
+            destroy() {
+                for (const subscription of subscriptions) {
+                    subscription.destroy();
+                }
+            },
+        };
+    }
+    // `document` should never be the base, it's just an easy way to define "global event listeners"
+    const baseElement = base instanceof Document ? base.documentElement : base;
+    // Handle the regular Element usage
+    const capture = Boolean(typeof options === 'object' ? options.capture : options);
+    const listenerFn = (event) => {
+        const delegateTarget = safeClosest(event, selector);
+        if (delegateTarget) {
+            event.delegateTarget = delegateTarget;
+            callback.call(baseElement, event);
+        }
+    };
+    // Drop unsupported `once` option https://github.com/fregante/delegate-it/pull/28#discussion_r863467939
+    if (typeof options === 'object') {
+        delete options.once;
+    }
+    const setup = JSON.stringify({ selector, type, capture });
+    const isAlreadyListening = editLedger(true, baseElement, callback, setup);
+    const delegateSubscription = {
+        destroy() {
+            baseElement.removeEventListener(type, listenerFn, options);
+            editLedger(false, baseElement, callback, setup);
+        },
+    };
+    if (!isAlreadyListening) {
+        baseElement.addEventListener(type, listenerFn, options);
+    }
+    return delegateSubscription;
+}
+// export default delegate;
+
+window.delegate = delegate;
+})();

layouts/partials/footer.html

@@ -26,6 +26,27 @@
 
 {{- partial "extend_footer.html" . }}
 
+{{/* Load delegate script */}}
+{{- $delegate := resources.Get "js/delegate-it.js" }}
+<script src="{{ $delegate.RelPermalink }}" data-no-instant
+  {{- if site.Params.assets.disableFingerprinting }}integrity="{{ $delegate.Data.Integrity }}"{{- end }}
+></script>
+
+<script>
+  (function() {
+    /* theme toggle */
+    const disableThemeToggle = '{{ if site.Params.disableThemeToggle }}1{{ end }}' == '1';
+    if (disableThemeToggle) {
+      return;
+    }
+
+    // listen to toggle button
+    document.getElementById("theme-toggle").addEventListener("click", () => {
+      window.dispatchEvent(new CustomEvent('toggle-theme'));
+    });
+  })();
+</script>
+
 <script>
   (function () {
     let menu = document.getElementById('menu')
@@ -75,20 +96,6 @@
 </script>
 {{- end }}
 
-{{- if (not site.Params.disableThemeToggle) }}
-<script>
-  document.getElementById("theme-toggle").addEventListener("click", () => {
-    if (document.body.className.includes("dark")) {
-      document.body.classList.remove('dark');
-      localStorage.setItem("pref-theme", 'light');
-    } else {
-      document.body.classList.add('dark');
-      localStorage.setItem("pref-theme", 'dark');
-    }
-  })
-</script>
-{{- end }}
-
 {{- /* Base64Email */}}
 {{- if (.Param "MaskedEmail") }}
 <script>

layouts/partials/header.html

@@ -1,43 +1,61 @@
-{{- /* theme-toggle is enabled */}}
-{{- if (not site.Params.disableThemeToggle) }}
-{{- /* theme is light */}}
-{{- if (eq site.Params.defaultTheme "light") }}
-<script>
-    if (localStorage.getItem("pref-theme") === "dark") {
+<script data-no-instant>
+function switchTheme(theme) {
+  switch (theme) {
+    case 'light':
+      document.body.classList.remove('dark');
+      break;
+    case 'dark':
+      document.body.classList.add('dark');
+      break;
+    // auto
+    default:
+      if (window.matchMedia('(prefers-color-scheme: dark)').matches) {
         document.body.classList.add('dark');
-    }
+      }
+  }
+}
 
+function isDarkTheme() {
+  return document.body.className.includes("dark");
+}
+
+function getPrefTheme() {
+  return localStorage.getItem("pref-theme");
+}
+
+function setPrefTheme(theme) {
+  switchTheme(theme)
+  localStorage.setItem("pref-theme", theme);
+}
+
+const toggleThemeCallbacks = []
+toggleThemeCallbacks.push((isDark) => {
+  // console.log('window toggle-theme')
+  if (isDark) {
+    setPrefTheme('light');
+  } else {
+    setPrefTheme('dark');
+  }
+})
+
+// listen to set-theme event,
+// because window is never changed by InstantClick,
+// we add the listener to window to ensure the event is always received
+window.addEventListener('toggle-theme', function() {
+  const isDark = isDarkTheme()
+  toggleThemeCallbacks.forEach(callback => callback(isDark))
+});
 </script>
-{{- /* theme is dark */}}
-{{- else if (eq site.Params.defaultTheme "dark") }}
 <script>
-    if (localStorage.getItem("pref-theme") === "light") {
-        document.body.classList.remove('dark')
-    }
+  // load theme, as early as possible
+  (function() {
+    const defaultTheme = '{{ site.Params.defaultTheme | default "light" }}';
+    const prefTheme = getPrefTheme();
+    const theme = prefTheme ? prefTheme : defaultTheme;
 
+    switchTheme(theme);
+  })();
 </script>
-{{- else }}
-{{- /* theme is auto */}}
-<script>
-    if (localStorage.getItem("pref-theme") === "dark") {
-        document.body.classList.add('dark');
-    } else if (localStorage.getItem("pref-theme") === "light") {
-        document.body.classList.remove('dark')
-    } else if (window.matchMedia('(prefers-color-scheme: dark)').matches) {
-        document.body.classList.add('dark');
-    }
-
-</script>
-{{- end }}
-{{- /* theme-toggle is disabled and theme is auto */}}
-{{- else if (and (ne site.Params.defaultTheme "light") (ne site.Params.defaultTheme "dark"))}}
-<script>
-    if (window.matchMedia('(prefers-color-scheme: dark)').matches) {
-        document.body.classList.add('dark');
-    }
-
-</script>
-{{- end }}
 
 <header class="header">
     <nav class="nav">