Toggle theme with HTML class

src/www/js/app.js

@@ -45,6 +45,8 @@ new Vue({
     currentRelease: null,
     latestRelease: null,
 
+    isDark: null,
+
     chartOptions: {
       chart: {
         background: 'transparent',
@@ -239,6 +241,16 @@ new Vue({
         .catch(err => alert(err.message || err.toString()))
         .finally(() => this.refresh().catch(console.error));
     },
+    toggleTheme() {
+        if (this.isDark) {
+          localStorage.theme = "light";
+          document.documentElement.classList.remove('dark');
+        } else {
+          localStorage.theme = "dark";
+          document.documentElement.classList.add('dark');
+        }
+        this.isDark = !this.isDark;
+    },
   },
   filters: {
     bytes,
@@ -247,6 +259,11 @@ new Vue({
     },
   },
   mounted() {
+    this.isDark = false;
+    if (localStorage.theme === 'dark') {
+      this.isDark = true;
+    }
+
     this.api = new API();
     this.api.getSession()
       .then(session => {