Fix animation for pipeline editor drawer on load

app/assets/javascripts/pipeline_editor/components/drawer/pipeline_editor_drawer.vue

@@ -28,7 +28,7 @@ export default {
   },
   data() {
     return {
-      isExpanded: true,
+      isExpanded: false,
       topPosition: 0,
     };
   },
@@ -49,8 +49,18 @@ export default {
   },
   mounted() {
     this.setTopPosition();
+    this.setInitialExpandState();
   },
   methods: {
+    setInitialExpandState() {
+      // We check in the local storage and if no value is defined, we want the default
+      // to be true. We want to explicitly set it to true here so that the drawer
+      // animates to open on load.
+      const localValue = localStorage.getItem(this.$options.localDrawerKey);
+      if (localValue === null) {
+        this.isExpanded = true;
+      }
+    },
     setTopPosition() {
       const navbarEl = document.querySelector('.js-navbar');
 
@@ -68,7 +78,7 @@ export default {
   <local-storage-sync v-model="isExpanded" :storage-key="$options.localDrawerKey" as-json>
     <aside
       aria-live="polite"
-      class="gl-fixed gl-right-0 gl-bg-gray-10 gl-shadow-drawer gl-transition-medium gl-border-l-solid gl-border-1 gl-border-gray-100 gl-h-full gl-z-index-3 gl-overflow-y-auto"
+      class="gl-fixed gl-right-0 gl-bg-gray-10 gl-shadow-drawer gl-transition-property-width gl-transition-duration-medium gl-border-l-solid gl-border-1 gl-border-gray-100 gl-h-full gl-z-index-3 gl-overflow-y-auto"
       :style="rootStyle"
     >
       <gl-button

spec/frontend/pipeline_editor/components/drawer/pipeline_editor_drawer_spec.js

@@ -38,6 +38,16 @@ describe('Pipeline editor drawer', () => {
     localStorage.clear();
   });
 
+  it('it sets the drawer to be opened by default', async () => {
+    createComponent();
+
+    expect(findDrawerContent().exists()).toBe(false);
+
+    await nextTick();
+
+    expect(findDrawerContent().exists()).toBe(true);
+  });
+
   describe('when the drawer is collapsed', () => {
     beforeEach(async () => {
       createComponent();
@@ -100,10 +110,15 @@ describe('Pipeline editor drawer', () => {
 
   describe('local storage', () => {
     it('saves the drawer expanded value to local storage', async () => {
+      localStorage.setItem(DRAWER_EXPANDED_KEY, 'false');
+
       createComponent();
       await clickToggleBtn();
 
-      expect(localStorage.setItem.mock.calls).toEqual([[DRAWER_EXPANDED_KEY, 'false']]);
+      expect(localStorage.setItem.mock.calls).toEqual([
+        [DRAWER_EXPANDED_KEY, 'false'],
+        [DRAWER_EXPANDED_KEY, 'true'],
+      ]);
     });
 
     it('loads the drawer collapsed when local storage is set to `false`, ', async () => {