fix(query-core): treat undefined object properties as missing in partialMatchKey

packages/query-core/src/__tests__/utils.test.tsx

@@ -165,6 +165,30 @@ describe('core/utils', () => {
       const b = [{ a: null, c: 'c', d: [{ d: 'd ' }] }]
       expect(partialMatchKey(a, b)).toEqual(false)
     })
+
+    it('should treat object property set to undefined as missing property', () => {
+      const a = ['todos']
+      const b = ['todos', { filter: undefined }]
+      expect(partialMatchKey(a, b)).toEqual(true)
+    })
+
+    it('should treat empty object and object with undefined values as equivalent', () => {
+      const a = ['todos', {}]
+      const b = ['todos', { filter: undefined }]
+      expect(partialMatchKey(a, b)).toEqual(true)
+    })
+
+    it('should match queries with specific filter when using undefined filter', () => {
+      const a = ['todos', { filter: 'done' }]
+      const b = ['todos', { filter: undefined }]
+      expect(partialMatchKey(a, b)).toEqual(true)
+    })
+
+    it('should not match when filter has a non-undefined value that differs', () => {
+      const a = ['todos', { filter: 'active' }]
+      const b = ['todos', { filter: 'done' }]
+      expect(partialMatchKey(a, b)).toEqual(false)
+    })
   })
 
   describe('replaceEqualDeep', () => {

packages/query-core/src/utils.ts

@@ -256,7 +256,23 @@ export function partialMatchKey(a: any, b: any): boolean {
   }
 
   if (a && b && typeof a === 'object' && typeof b === 'object') {
-    return Object.keys(b).every((key) => partialMatchKey(a[key], b[key]))
+    return Object.keys(b).every((key) => {
+      if (b[key] === undefined) {
+        return true
+      }
+      if (
+        a[key] === undefined &&
+        b[key] &&
+        typeof b[key] === 'object' &&
+        Object.values(b[key]).every((v: any) => v === undefined)
+      ) {
+        return true
+      }
+      if (a[key] === undefined) {
+        return false
+      }
+      return partialMatchKey(a[key], b[key])
+    })
   }
 
   return false