check active nodes

src/demos/HandleExtensions/index.vue

@@ -7,7 +7,7 @@
       <button @click="editor.redo().focus()">
         redo
       </button>
-      <button @click="editor.bold().focus()">
+      <button @click="editor.bold().focus()" :class="{ 'is-active': editor.isActive.bold() }">
         bold
       </button>
     </div>

src/layouts/Default.vue

@@ -49,6 +49,11 @@ body {
   outline: none;
 }
 
+.is-active {
+  background: black;
+  color: white;
+}
+
 // :not(pre) > code[class*="language-"], pre[class*="language-"] {
 //   background-color: $colorBlack;
 // }