Add 'cloneData' option to buildMemoryStorage

src/storage/memory.ts

@@ -1,5 +1,5 @@
 import { buildStorage, canStale, isExpired } from './build';
-import type { AxiosStorage, StorageValue } from './types';
+import type { AxiosStorage, NotEmptyStorageValue, StorageValue } from './types';
 
 /**
  * Modern function to natively deep clone.
@@ -30,8 +30,10 @@ declare const structuredClone: (<T>(value: T) => T) | undefined;
  * delete memoryStorage.data[id];
  * ```
  *
- * @param {boolean} cloneData If the data returned by `find()` should be cloned to avoid
- *   mutating the original data outside the `set()` method.
+ * @param {boolean | 'double'} cloneData Use `true` if the data returned by `find()`
+ *   should be cloned to avoid mutating the original data outside the `set()` method. Use
+ *   `'double'` to also clone before saving value in storage using `set()`. Disabled is
+ *   default
  * @param {number | false} cleanupInterval The interval in milliseconds to run a
  *   setInterval job of cleaning old entries. If false, the job will not be created.
  *   Disabled is default
@@ -41,7 +43,7 @@ declare const structuredClone: (<T>(value: T) => T) | undefined;
  *   usage. Disabled is default
  */
 export function buildMemoryStorage(
-  cloneData = false,
+  cloneData: boolean | 'double' = false,
   cleanupInterval: number | false = false,
   maxEntries: number | false = false
 ) {
@@ -67,6 +69,17 @@ export function buildMemoryStorage(
         }
       }
 
+      /* istanbul ignore if 'only available on super recent browsers' */
+      if (cloneData === 'double' && value !== undefined) {
+        // Clone the value before storing to prevent future mutations
+        // from affecting cached data.
+        if (typeof structuredClone === 'function') {
+          value = structuredClone(value);
+        } else {
+          value = JSON.parse(JSON.stringify(value)) as NotEmptyStorageValue;
+        }
+      }
+
       storage.data[key] = value;
     },
 

test/storage/memory.test.ts

@@ -38,6 +38,35 @@ describe('tests memory storage', () => {
     expect(result2.data?.data).toBe('data');
   });
 
+  // Expects that a when value saved using storage.set() is has his inner properties updated,
+  // a request to storage.get() should return unmodified value.
+  //
+  // https://github.com/arthurfiorette/axios-cache-interceptor/issues/580
+  it('ensures set() also clones data when cloneData is double', async () => {
+    const storage = buildMemoryStorage('double');
+
+    const data = { ...EMPTY_RESPONSE, data: 'data' };
+    await storage.set('key', {
+      state: 'cached',
+      createdAt: Date.now(),
+      ttl: 1000 * 60 * 5, // 5 Minutes
+      data: data
+    });
+
+    data.data = 'another data';
+
+    expect(storage.data['key']).not.toBeNull();
+    expect(storage.data['key']!.state).toBe('cached');
+    expect(storage.data['key']!.data).not.toBeNull();
+    expect(storage.data['key']!.data!.data).toBe('data');
+
+    const result = (await storage.get('key')) as CachedStorageValue;
+
+    expect(result).not.toBeNull();
+    expect(result.state).toBe('cached');
+    expect(result.data.data).toBe('data');
+  });
+
   it('tests cleanup function', async () => {
     const storage = buildMemoryStorage(false, 500);