Progressively load releases on the Releases page

app/assets/javascripts/releases/components/app_index_apollo_client.vue

@@ -33,7 +33,34 @@ export default {
     },
   },
   apollo: {
-    graphqlResponse: {
+    /**
+     * The same query as `fullGraphqlResponse`, except that it limits its
+     * results to a single item. This causes this request to complete much more
+     * quickly than `fullGraphqlResponse`, which allows the page to show
+     * meaningful content to the user much earlier.
+     */
+    singleGraphqlResponse: {
+      query: allReleasesQuery,
+      // This trick only works when paginating _forward_.
+      // When paginating backwards, limiting the query to a single item loads
+      // the _last_ item in the page, which is not useful for our purposes.
+      skip() {
+        return !this.includeSingleQuery;
+      },
+      variables() {
+        return {
+          ...this.queryVariables,
+          first: 1,
+        };
+      },
+      update(data) {
+        return { data };
+      },
+      error() {
+        this.singleRequestError = true;
+      },
+    },
+    fullGraphqlResponse: {
       query: allReleasesQuery,
       variables() {
         return this.queryVariables;
@@ -42,7 +69,7 @@ export default {
         return { data };
       },
       error(error) {
-        this.hasError = true;
+        this.fullRequestError = true;
 
         createFlash({
           message: this.$options.i18n.errorMessage,
@@ -54,7 +81,8 @@ export default {
   },
   data() {
     return {
-      hasError: false,
+      singleRequestError: false,
+      fullRequestError: false,
       cursors: {
         before: getParameterByName('before'),
         after: getParameterByName('after'),
@@ -83,42 +111,66 @@ export default {
         sort: this.sort,
       };
     },
-    isLoading() {
-      return this.$apollo.queries.graphqlResponse.loading;
+    /**
+     * @returns {Boolean} Whether or not to request/include
+     * the results of the single-item query
+     */
+    includeSingleQuery() {
+      return Boolean(!this.cursors.before || this.cursors.after);
+    },
+    isSingleRequestLoading() {
+      return this.$apollo.queries.singleGraphqlResponse.loading;
+    },
+    isFullRequestLoading() {
+      return this.$apollo.queries.fullGraphqlResponse.loading;
+    },
+    /**
+     * @returns {Boolean} `true` if the `singleGraphqlResponse`
+     * query has finished loading without errors
+     */
+    isSingleRequestLoaded() {
+      return Boolean(!this.isSingleRequestLoading && this.singleGraphqlResponse?.data.project);
+    },
+    /**
+     * @returns {Boolean} `true` if the `fullGraphqlResponse`
+     * query has finished loading without errors
+     */
+    isFullRequestLoaded() {
+      return Boolean(!this.isFullRequestLoading && this.fullGraphqlResponse?.data.project);
     },
     releases() {
-      if (!this.graphqlResponse || this.hasError) {
-        return [];
+      if (this.isFullRequestLoaded) {
+        return convertAllReleasesGraphQLResponse(this.fullGraphqlResponse).data;
+      }
+
+      if (this.isSingleRequestLoaded && this.includeSingleQuery) {
+        return convertAllReleasesGraphQLResponse(this.singleGraphqlResponse).data;
       }
 
-      return convertAllReleasesGraphQLResponse(this.graphqlResponse).data;
+      return [];
     },
     pageInfo() {
-      if (!this.graphqlResponse || this.hasError) {
+      if (!this.isFullRequestLoaded) {
         return {
           hasPreviousPage: false,
           hasNextPage: false,
         };
       }
 
-      return this.graphqlResponse.data.project.releases.pageInfo;
+      return this.fullGraphqlResponse.data.project.releases.pageInfo;
     },
     shouldRenderEmptyState() {
-      return !this.releases.length && !this.hasError && !this.isLoading;
-    },
-    shouldRenderSuccessState() {
-      return this.releases.length && !this.isLoading && !this.hasError;
+      return this.isFullRequestLoaded && this.releases.length === 0;
     },
     shouldRenderLoadingIndicator() {
-      return this.isLoading && !this.hasError;
-    },
-    shouldRenderPagination() {
       return (
-        !this.isLoading &&
-        !this.hasError &&
-        (this.pageInfo.hasPreviousPage || this.pageInfo.hasNextPage)
+        (this.isSingleRequestLoading && !this.singleRequestError && !this.isFullRequestLoaded) ||
+        (this.isFullRequestLoading && !this.fullRequestError)
       );
     },
+    shouldRenderPagination() {
+      return this.isFullRequestLoaded && !this.shouldRenderEmptyState;
+    },
   },
   created() {
     this.updateQueryParamsFromUrl();
@@ -130,7 +182,7 @@ export default {
   },
   methods: {
     getReleaseKey(release, index) {
-      return [release.tagNamerstrs, release.name, index].join('|');
+      return [release.tagName, release.name, index].join('|');
     },
     updateQueryParamsFromUrl() {
       this.cursors.before = getParameterByName('before');
@@ -191,18 +243,16 @@ export default {
       >
     </div>
 
-    <release-skeleton-loader v-if="shouldRenderLoadingIndicator" />
+    <releases-empty-state v-if="shouldRenderEmptyState" />
 
-    <releases-empty-state v-else-if="shouldRenderEmptyState" />
+    <release-block
+      v-for="(release, index) in releases"
+      :key="getReleaseKey(release, index)"
+      :release="release"
+      :class="{ 'linked-card': releases.length > 1 && index !== releases.length - 1 }"
+    />
 
-    <div v-else-if="shouldRenderSuccessState">
-      <release-block
-        v-for="(release, index) in releases"
-        :key="getReleaseKey(release, index)"
-        :release="release"
-        :class="{ 'linked-card': releases.length > 1 && index !== releases.length - 1 }"
-      />
-    </div>
+    <release-skeleton-loader v-if="shouldRenderLoadingIndicator" />
 
     <releases-pagination-apollo-client
       v-if="shouldRenderPagination"

app/assets/javascripts/releases/mount_index.js

@@ -14,7 +14,19 @@ export default () => {
     Vue.use(VueApollo);
 
     const apolloProvider = new VueApollo({
-      defaultClient: createDefaultClient(),
+      defaultClient: createDefaultClient(
+        {},
+        {
+          // This page attempts to decrease the perceived loading time
+          // by sending two requests: one request for the first item only (which
+          // completes relatively quickly), and one for all the items (which is slower).
+          // By default, Apollo Client batches these requests together, which defeats
+          // the purpose of making separate requests. So we explicitly
+          // disable batching on this page.
+          batchMax: 1,
+          assumeImmutableResults: true,
+        },
+      ),
     });
 
     return new Vue({

spec/frontend/fixtures/releases.rb

@@ -100,6 +100,17 @@ RSpec.describe 'Releases (JavaScript fixtures)' do
            link_type: :image)
   end
 
+  let_it_be(:another_release) do
+    create(:release,
+           project: project,
+           tag: 'v1.2',
+           name: 'The second release',
+           author: admin,
+           description: 'An okay release :shrug:',
+           created_at: Time.zone.parse('2019-01-03'),
+           released_at: Time.zone.parse('2019-01-10'))
+  end
+
   after(:all) do
     remove_repository(project)
   end

spec/frontend/releases/__snapshots__/util_spec.js.snap

@@ -3,6 +3,58 @@
 exports[`releases/util.js convertAllReleasesGraphQLResponse matches snapshot 1`] = `
 Object {
   "data": Array [
+    Object {
+      "_links": Object {
+        "closedIssuesUrl": "http://localhost/releases-namespace/releases-project/-/issues?release_tag=v1.2&scope=all&state=closed",
+        "closedMergeRequestsUrl": "http://localhost/releases-namespace/releases-project/-/merge_requests?release_tag=v1.2&scope=all&state=closed",
+        "editUrl": "http://localhost/releases-namespace/releases-project/-/releases/v1.2/edit",
+        "mergedMergeRequestsUrl": "http://localhost/releases-namespace/releases-project/-/merge_requests?release_tag=v1.2&scope=all&state=merged",
+        "openedIssuesUrl": "http://localhost/releases-namespace/releases-project/-/issues?release_tag=v1.2&scope=all&state=opened",
+        "openedMergeRequestsUrl": "http://localhost/releases-namespace/releases-project/-/merge_requests?release_tag=v1.2&scope=all&state=opened",
+        "self": "http://localhost/releases-namespace/releases-project/-/releases/v1.2",
+        "selfUrl": "http://localhost/releases-namespace/releases-project/-/releases/v1.2",
+      },
+      "assets": Object {
+        "count": 4,
+        "links": Array [],
+        "sources": Array [
+          Object {
+            "format": "zip",
+            "url": "http://localhost/releases-namespace/releases-project/-/archive/v1.2/releases-project-v1.2.zip",
+          },
+          Object {
+            "format": "tar.gz",
+            "url": "http://localhost/releases-namespace/releases-project/-/archive/v1.2/releases-project-v1.2.tar.gz",
+          },
+          Object {
+            "format": "tar.bz2",
+            "url": "http://localhost/releases-namespace/releases-project/-/archive/v1.2/releases-project-v1.2.tar.bz2",
+          },
+          Object {
+            "format": "tar",
+            "url": "http://localhost/releases-namespace/releases-project/-/archive/v1.2/releases-project-v1.2.tar",
+          },
+        ],
+      },
+      "author": Object {
+        "avatarUrl": "https://www.gravatar.com/avatar/16f8e2050ce10180ca571c2eb19cfce2?s=80&d=identicon",
+        "username": "administrator",
+        "webUrl": "http://localhost/administrator",
+      },
+      "commit": Object {
+        "shortId": "b83d6e39",
+        "title": "Merge branch 'branch-merged' into 'master'",
+      },
+      "commitPath": "http://localhost/releases-namespace/releases-project/-/commit/b83d6e391c22777fca1ed3012fce84f633d7fed0",
+      "descriptionHtml": "<p data-sourcepos=\\"1:1-1:23\\" dir=\\"auto\\">An okay release <gl-emoji title=\\"shrug\\" data-name=\\"shrug\\" data-unicode-version=\\"9.0\\">🤷</gl-emoji></p>",
+      "evidences": Array [],
+      "milestones": Array [],
+      "name": "The second release",
+      "releasedAt": "2019-01-10T00:00:00Z",
+      "tagName": "v1.2",
+      "tagPath": "/releases-namespace/releases-project/-/tags/v1.2",
+      "upcomingRelease": true,
+    },
     Object {
       "_links": Object {
         "closedIssuesUrl": "http://localhost/releases-namespace/releases-project/-/issues?release_tag=v1.1&scope=all&state=closed",
@@ -124,7 +176,7 @@ Object {
     "endCursor": "eyJyZWxlYXNlZF9hdCI6IjIwMTgtMTItMTAgMDA6MDA6MDAuMDAwMDAwMDAwIFVUQyIsImlkIjoiMSJ9",
     "hasNextPage": false,
     "hasPreviousPage": false,
-    "startCursor": "eyJyZWxlYXNlZF9hdCI6IjIwMTgtMTItMTAgMDA6MDA6MDAuMDAwMDAwMDAwIFVUQyIsImlkIjoiMSJ9",
+    "startCursor": "eyJyZWxlYXNlZF9hdCI6IjIwMTktMDEtMTAgMDA6MDA6MDAuMDAwMDAwMDAwIFVUQyIsImlkIjoiMiJ9",
   },
 }
 `;