Avoid freezing user-provided scalar field values.

apollographql · Aug 21, 2019 · af94014 · af94014
1 parent 2643dbb
commit af94014
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Showing 2 changed files with 42 additions and 1 deletion.
diff --git a/packages/apollo-cache-inmemory/src/__tests__/writeToStore.ts b/packages/apollo-cache-inmemory/src/__tests__/writeToStore.ts
@@ -20,6 +20,7 @@ import { StoreWriter } from '../writeToStore';
 import { defaultNormalizedCacheFactory } from '../entityCache';
 
 import { makeReference } from '../helpers';
+import { InMemoryCache } from '../inMemoryCache';
 
 export function withWarning(func: Function, regex?: RegExp) {
   let message: string = null as never;
@@ -1862,4 +1863,40 @@ describe('writing to the store', () => {
       },
     });
   });
+
+  it('should not deep-freeze scalar objects', () => {
+    const query = gql`
+      query {
+        scalarFieldWithObjectValue
+      }
+    `;
+
+    const scalarObject = {
+      a: 1,
+      b: [2, 3],
+      c: {
+        d: 4,
+        e: 5,
+      },
+    };
+
+    const cache = new InMemoryCache();
+
+    cache.writeQuery({
+      query,
+      data: {
+        scalarFieldWithObjectValue: scalarObject,
+      },
+    });
+
+    expect(Object.isFrozen(scalarObject)).toBe(false);
+    expect(Object.isFrozen(scalarObject.b)).toBe(false);
+    expect(Object.isFrozen(scalarObject.c)).toBe(false);
+
+    const result = cache.readQuery<any>({ query });
+    expect(result.scalarFieldWithObjectValue).not.toBe(scalarObject);
+    expect(Object.isFrozen(result.scalarFieldWithObjectValue)).toBe(true);
+    expect(Object.isFrozen(result.scalarFieldWithObjectValue.b)).toBe(true);
+    expect(Object.isFrozen(result.scalarFieldWithObjectValue.c)).toBe(true);
+  });
 });
diff --git a/packages/apollo-cache-inmemory/src/writeToStore.ts b/packages/apollo-cache-inmemory/src/writeToStore.ts
@@ -15,6 +15,7 @@ import {
   StoreValue,
   DeepMerger,
   getTypenameFromResult,
+  cloneDeep,
 } from 'apollo-utilities';
 
 import { invariant, InvariantError } from 'ts-invariant';
@@ -233,7 +234,10 @@ export class StoreWriter {
     context: WriteContext,
   ): StoreValue {
     if (!field.selectionSet || value === null) {
-      return value;
+      // In development, we need to clone scalar values so that they can be
+      // safely frozen with maybeDeepFreeze in readFromStore.ts. In production,
+      // it's cheaper to store the scalar values directly in the cache.
+      return process.env.NODE_ENV === 'production' ? value : cloneDeep(value);
     }
 
     if (Array.isArray(value)) {