first commit

public/scripts/AppCollapsible.js

@@ -0,0 +1,29 @@
+/* global VT */
+window.VT = window.VT || {};
+
+VT.AppCollapsible = function (el) {
+  var state = {
+    show: true,
+  };
+
+  el.querySelector('.bar > .toggle').addEventListener('click', function () {
+    update({ show: !state.show });
+  });
+
+  el.appCollapsible = {
+    update: update,
+  };
+
+  function update(next) {
+    Object.assign(state, next);
+
+    el.querySelector('.bar > .toggle > .app-icon').classList.toggle(
+      '-r180',
+      state.show
+    );
+
+    el.querySelectorAll('.body').forEach(function (el) {
+      el.style.height = state.show ? el.children[0].offsetHeight + 'px' : '0';
+    });
+  }
+};