1 files changed, 83 insertions, 1 deletions

diff --git a/app/assets/javascripts/work_items/graphql/provider.js b/app/assets/javascripts/work_items/graphql/provider.js
index 3c2955ce1e2..09d929faae2 100644
--- a/app/assets/javascripts/work_items/graphql/provider.js
+++ b/app/assets/javascripts/work_items/graphql/provider.js
@@ -1,11 +1,93 @@
+import produce from 'immer';
 import Vue from 'vue';
 import VueApollo from 'vue-apollo';
 import createDefaultClient from '~/lib/graphql';
+import { WIDGET_TYPE_ASSIGNEE } from '../constants';
+import typeDefs from './typedefs.graphql';
+import workItemQuery from './work_item.query.graphql';
+
+export const temporaryConfig = {
+  typeDefs,
+  cacheConfig: {
+    possibleTypes: {
+      LocalWorkItemWidget: ['LocalWorkItemAssignees'],
+    },
+    typePolicies: {
+      WorkItem: {
+        fields: {
+          mockWidgets: {
+            read(widgets) {
+              return (
+                widgets || [
+                  {
+                    __typename: 'LocalWorkItemAssignees',
+                    type: 'ASSIGNEES',
+                    nodes: [
+                      {
+                        __typename: 'UserCore',
+                        id: 'gid://gitlab/User/1',
+                        avatarUrl: '',
+                        webUrl: '',
+                        // eslint-disable-next-line @gitlab/require-i18n-strings
+                        name: 'John Doe',
+                        username: 'doe_I',
+                      },
+                      {
+                        __typename: 'UserCore',
+                        id: 'gid://gitlab/User/2',
+                        avatarUrl: '',
+                        webUrl: '',
+                        // eslint-disable-next-line @gitlab/require-i18n-strings
+                        name: 'Marcus Rutherford',
+                        username: 'ruthfull',
+                      },
+                    ],
+                  },
+                  {
+                    __typename: 'LocalWorkItemWeight',
+                    type: 'WEIGHT',
+                    weight: 0,
+                  },
+                ]
+              );
+            },
+          },
+        },
+      },
+    },
+  },
+};
+
+export const resolvers = {
+  Mutation: {
+    localUpdateWorkItem(_, { input }, { cache }) {
+      const sourceData = cache.readQuery({
+        query: workItemQuery,
+        variables: { id: input.id },
+      });
+
+      const data = produce(sourceData, (draftData) => {
+        const assigneesWidget = draftData.workItem.mockWidgets.find(
+          (widget) => widget.type === WIDGET_TYPE_ASSIGNEE,
+        );
+        assigneesWidget.nodes = assigneesWidget.nodes.filter((assignee) =>
+          input.assigneeIds.includes(assignee.id),
+        );
+      });
+
+      cache.writeQuery({
+        query: workItemQuery,
+        variables: { id: input.id },
+        data,
+      });
+    },
+  },
+};
 
 export function createApolloProvider() {
   Vue.use(VueApollo);
 
-  const defaultClient = createDefaultClient();
+  const defaultClient = createDefaultClient(resolvers, temporaryConfig);
 
   return new VueApollo({
     defaultClient,