Write field shouldn't rewrite the object reference if the field value…

… is the same
apollographql · Jul 18, 2016 · 99284ba · 99284ba
1 parent e69d151
commit 99284ba
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Showing 3 changed files with 41 additions and 3 deletions.
diff --git a/src/data/writeToStore.ts b/src/data/writeToStore.ts
@@ -281,5 +281,7 @@ function writeFieldToStore({
     [storeFieldName]: storeValue,
   }) as StoreObject;
 
-  store[dataId] = newStoreObj;
+  if (!store[dataId] || storeValue !== store[dataId][storeFieldName]) {
+    store[dataId] = newStoreObj;
+  }
 }
diff --git a/test/optimistic.ts b/test/optimistic.ts
@@ -3,7 +3,7 @@ const { assert } = chai;
 
 import mockNetworkInterface from './mocks/mockNetworkInterface';
 import ApolloClient, { addTypename } from '../src';
-import { MutationBehaviorReducerArgs, MutationBehavior } from '../src/data/mutationResults';
+import { MutationBehaviorReducerArgs, MutationBehavior, MutationQueryReducersMap } from '../src/data/mutationResults';
 import { NormalizedCache, StoreObject } from '../src/data/store';
 
 import assign = require('lodash.assign');
@@ -745,7 +745,7 @@ describe('optimistic mutation results', () => {
             state.todoList.todos.unshift(mResult.data.createTodo);
             return state;
           },
-        };
+        } as MutationQueryReducersMap;
         const promise = client.mutate({
           mutation,
           optimisticResponse,

diff --git a/test/writeToStore.ts b/test/writeToStore.ts
@@ -15,6 +15,10 @@ import {
   getIdField,
 } from '../src/data/extensions';
 
+import {
+  NormalizedCache,
+} from '../src/data/store';
+
 import {
   Selection,
   Field,
@@ -816,4 +820,36 @@ describe('writing to the store', () => {
       });
     });
   });
+
+  it('does not change object references if the value is the same', () => {
+    const fragment = gql`
+      fragment Item on ItemType {
+        id,
+        stringField,
+        numberField,
+        nullField
+      }
+    `;
+
+    const result = {
+      id: 'abcd',
+      stringField: 'This is a string!',
+      numberField: 5,
+      nullField: null,
+    };
+    const store = writeFragmentToStore({
+      fragment,
+      result: _.cloneDeep(result),
+    });
+
+    const newStore = writeFragmentToStore({
+      fragment,
+      result: _.cloneDeep(result),
+      store: _.assign({}, store) as NormalizedCache,
+    });
+
+    Object.keys(store).forEach((field) => {
+      assert.equal(store[field], newStore[field], 'references are the same');
+    });
+  });
 });