Update package title to react to resize

app/assets/javascripts/packages_and_registries/package_registry/components/details/package_title.vue

 <script>
-import { GlIcon, GlSprintf, GlBadge } from '@gitlab/ui';
+import { GlIcon, GlSprintf, GlBadge, GlResizeObserverDirective } from '@gitlab/ui';
 import { GlBreakpointInstance } from '@gitlab/ui/dist/utils';
 import { numberToHumanSize } from '~/lib/utils/number_utils';
 import { __ } from '~/locale';
@@ -21,6 +21,9 @@ export default {
     GlBadge,
     TimeAgoTooltip,
   },
+  directives: {
+    GlResizeObserver: GlResizeObserverDirective,
+  },
   i18n: {
     packageInfo: __('v%{version} published %{timeAgo}'),
   },
@@ -60,18 +63,26 @@ export default {
     },
   },
   mounted() {
-    this.isDesktop = GlBreakpointInstance.isDesktop();
+    this.checkBreakpoints();
   },
   methods: {
     dynamicSlotName(index) {
       return `metadata-tag${index}`;
     },
+    checkBreakpoints() {
+      this.isDesktop = GlBreakpointInstance.isDesktop();
+    },
   },
 };
 </script>
 
 <template>
-  <title-area :title="packageEntity.name" :avatar="packageIcon" data-qa-selector="package_title">
+  <title-area
+    v-gl-resize-observer="checkBreakpoints"
+    :title="packageEntity.name"
+    :avatar="packageIcon"
+    data-qa-selector="package_title"
+  >
     <template #sub-header>
       <gl-icon name="eye" class="gl-mr-3" />
       <span data-testid="sub-header">

app/assets/javascripts/vue_shared/components/registry/title_area.vue

 <script>
 import { GlAvatar, GlSprintf, GlLink, GlSkeletonLoader } from '@gitlab/ui';
+import { isEqual } from 'lodash';
 
 export default {
   name: 'TitleArea',
@@ -36,13 +37,21 @@ export default {
       metadataSlots: [],
     };
   },
-  async mounted() {
-    const METADATA_PREFIX = 'metadata-';
-    this.metadataSlots = Object.keys(this.$slots).filter((k) => k.startsWith(METADATA_PREFIX));
+  mounted() {
+    this.recalculateMetadataSlots();
+  },
+  updated() {
+    this.recalculateMetadataSlots();
+  },
+  methods: {
+    recalculateMetadataSlots() {
+      const METADATA_PREFIX = 'metadata-';
+      const metadataSlots = Object.keys(this.$slots).filter((k) => k.startsWith(METADATA_PREFIX));
 
-    // we need to wait for next tick to ensure that dynamic names slots are picked up
-    await this.$nextTick();
-    this.metadataSlots = Object.keys(this.$slots).filter((k) => k.startsWith(METADATA_PREFIX));
+      if (!isEqual(metadataSlots, this.metadataSlots)) {
+        this.metadataSlots = metadataSlots;
+      }
+    },
   },
 };
 </script>

spec/frontend/packages_and_registries/package_registry/components/details/__snapshots__/package_title_spec.js.snap

@@ -177,15 +177,6 @@ exports[`PackageTitle renders without tags 1`] = `
             texttooltip=""
           />
         </div>
-        <div
-          class="gl-display-flex gl-align-items-center gl-mr-5"
-        >
-          <package-tags-stub
-            hidelabel="true"
-            tagdisplaylimit="2"
-            tags="[object Object],[object Object],[object Object]"
-          />
-        </div>
       </div>
     </div>
      

spec/frontend/packages_and_registries/package_registry/components/details/package_title_spec.js

 import { GlIcon, GlSprintf } from '@gitlab/ui';
 import { GlBreakpointInstance } from '@gitlab/ui/dist/utils';
+import { createMockDirective, getBinding } from 'helpers/vue_mock_directive';
 import { shallowMountExtended } from 'helpers/vue_test_utils_helper';
 import PackageTags from '~/packages/shared/components/package_tags.vue';
 import PackageTitle from '~/packages_and_registries/package_registry/components/details/package_title.vue';
@@ -30,6 +31,9 @@ describe('PackageTitle', () => {
         TitleArea,
         GlSprintf,
       },
+      directives: {
+        GlResizeObserver: createMockDirective(),
+      },
     });
     return wrapper.vm.$nextTick();
   }
@@ -51,7 +55,7 @@ describe('PackageTitle', () => {
 
   describe('renders', () => {
     it('without tags', async () => {
-      await createComponent();
+      await createComponent({ ...packageData(), packageFiles: { nodes: packageFiles() } });
 
       expect(wrapper.element).toMatchSnapshot();
     });
@@ -64,12 +68,26 @@ describe('PackageTitle', () => {
 
     it('with tags on mobile', async () => {
       jest.spyOn(GlBreakpointInstance, 'isDesktop').mockReturnValue(false);
+
       await createComponent();
 
       await wrapper.vm.$nextTick();
 
       expect(findPackageBadges()).toHaveLength(packageTags().length);
     });
+
+    it('when the page is resized', async () => {
+      await createComponent();
+
+      expect(findPackageBadges()).toHaveLength(0);
+
+      jest.spyOn(GlBreakpointInstance, 'isDesktop').mockReturnValue(false);
+      const { value } = getBinding(wrapper.element, 'gl-resize-observer');
+      value();
+
+      await wrapper.vm.$nextTick();
+      expect(findPackageBadges()).toHaveLength(packageTags().length);
+    });
   });
 
   describe('package title', () => {

spec/frontend/vue_shared/components/registry/title_area_spec.js

@@ -135,15 +135,16 @@ describe('title area', () => {
         },
       });
     };
+
     it('shows dynamic slots', async () => {
       mountComponent();
       // we manually add a new slot to simulate dynamic slots being evaluated after the initial mount
       wrapper.vm.$slots[DYNAMIC_SLOT] = createDynamicSlot();
 
+      // updating the slots like we do on line 141 does not cause the updated lifecycle-hook to be triggered
+      wrapper.vm.$forceUpdate();
       await wrapper.vm.$nextTick();
-      expect(findDynamicSlot().exists()).toBe(false);
 
-      await wrapper.vm.$nextTick();
       expect(findDynamicSlot().exists()).toBe(true);
     });
 
@@ -160,10 +161,8 @@ describe('title area', () => {
         'metadata-foo': wrapper.vm.$slots['metadata-foo'],
       };
 
-      await wrapper.vm.$nextTick();
-      expect(findDynamicSlot().exists()).toBe(false);
-      expect(findMetadataSlot('metadata-foo').exists()).toBe(true);
-
+      // updating the slots like we do on line 159 does not cause the updated lifecycle-hook to be triggered
+      wrapper.vm.$forceUpdate();
       await wrapper.vm.$nextTick();
 
       expect(findSlotOrderElements().at(0).attributes('data-testid')).toBe(DYNAMIC_SLOT);