fix: toMatchObject works with super getters (#10381)

Author: souldzin

CHANGELOG.md

@@ -4,6 +4,8 @@
 
 ### Fixes
 
+- `[expect]` Fix `toMatchObject` to work with inherited class getters ([#10381](https://github.com/facebook/jest/pull/10381))
+
 ### Chore & Maintenance
 
 ### Performance

packages/expect/src/__tests__/__snapshots__/matchers.test.js.snap

@@ -3988,6 +3988,18 @@ exports[`toMatchObject() {pass: false} expect({"a": "b"}).toMatchObject({"c": "d
 <d> }</>
 `;
 
+exports[`toMatchObject() {pass: false} expect({"a": "b"}).toMatchObject({"toString": Any<Function>}) 1`] = `
+<d>expect(</><r>received</><d>).</>toMatchObject<d>(</><g>expected</><d>)</>
+
+<g>- Expected - 0</>
+<r>+ Received + 1</>
+
+<d> Object {</>
+<r>+ "a": "b",</>
+<d> "toString": Any<Function>,</>
+<d> }</>
+`;
+
 exports[`toMatchObject() {pass: false} expect({"a": [{"a": "a", "b": "b"}]}).toMatchObject({"a": [{"a": "c"}]}) 1`] = `
 <d>expect(</><r>received</><d>).</>toMatchObject<d>(</><g>expected</><d>)</>
 
@@ -4246,6 +4258,13 @@ Expected: not <g>{"t": {"x": {"r": "r"}}}</>
 Received: <r>{"a": "b", "t": {"x": {"r": "r"}, "z": "z"}}</>
 `;
 
+exports[`toMatchObject() {pass: true} expect({"a": "b", "toString": [Function toString]}).toMatchObject({"toString": Any<Function>}) 1`] = `
+<d>expect(</><r>received</><d>).</>not<d>.</>toMatchObject<d>(</><g>expected</><d>)</>
+
+Expected: not <g>{"toString": Any<Function>}</>
+Received: <r>{"a": "b", "toString": [Function toString]}</>
+`;
+
 exports[`toMatchObject() {pass: true} expect({"a": "b"}).toMatchObject({"a": "b"}) 1`] = `
 <d>expect(</><r>received</><d>).</>not<d>.</>toMatchObject<d>(</><g>expected</><d>)</>
 
@@ -4314,13 +4333,27 @@ exports[`toMatchObject() {pass: true} expect({"a": undefined}).toMatchObject({"a
 Expected: not <g>{"a": undefined}</>
 `;
 
+exports[`toMatchObject() {pass: true} expect({}).toMatchObject({"a": undefined, "b": "b", "c": "c"}) 1`] = `
+<d>expect(</><r>received</><d>).</>not<d>.</>toMatchObject<d>(</><g>expected</><d>)</>
+
+Expected: not <g>{"a": undefined, "b": "b", "c": "c"}</>
+Received: <r>{}</>
+`;
+
 exports[`toMatchObject() {pass: true} expect({}).toMatchObject({"a": undefined, "b": "b"}) 1`] = `
 <d>expect(</><r>received</><d>).</>not<d>.</>toMatchObject<d>(</><g>expected</><d>)</>
 
 Expected: not <g>{"a": undefined, "b": "b"}</>
 Received: <r>{}</>
 `;
 
+exports[`toMatchObject() {pass: true} expect({}).toMatchObject({"d": 4}) 1`] = `
+<d>expect(</><r>received</><d>).</>not<d>.</>toMatchObject<d>(</><g>expected</><d>)</>
+
+Expected: not <g>{"d": 4}</>
+Received: <r>{}</>
+`;
+
 exports[`toMatchObject() {pass: true} expect(2015-11-30T00:00:00.000Z).toMatchObject(2015-11-30T00:00:00.000Z) 1`] = `
 <d>expect(</><r>received</><d>).</>not<d>.</>toMatchObject<d>(</><g>expected</><d>)</>
 

packages/expect/src/__tests__/matchers.test.js

@@ -1958,6 +1958,22 @@ describe('toMatchObject()', () => {
  }
  }
 
+ class Sub extends Foo {
+ get c() {
+ return 'c';
+ }
+ }
+
+ const withDefineProperty = (obj, key, val) => {
+ Object.defineProperty(obj, key, {
+ get() {
+ return val;
+ },
+ });
+
+ return obj;
+ };
+
  const testNotToMatchSnapshots = tuples => {
  tuples.forEach(([n1, n2]) => {
  it(`{pass: true} expect(${stringify(n1)}).toMatchObject(${stringify(
@@ -2082,6 +2098,12 @@ describe('toMatchObject()', () => {
  {a: 'b', c: 'd', [Symbol.for('jest')]: 'jest'},
  {a: 'b', c: 'd', [Symbol.for('jest')]: 'jest'},
  ],
+ // These snapshots will show {} as the object because the properties
+ // are not enumerable. We will need to somehow make the serialization of
+ // these keys a little smarter before reporting accurately.
+ [new Sub(), {a: undefined, b: 'b', c: 'c'}],
+ [withDefineProperty(new Sub(), 'd', 4), {d: 4}],
+ [{a: 'b', toString() {}}, {toString: jestExpect.any(Function)}],
  ]);
 
  testToMatchSnapshots([
@@ -2129,6 +2151,7 @@ describe('toMatchObject()', () => {
  {a: 'b', c: 'd', [Symbol.for('jest')]: 'jest'},
  {a: 'c', [Symbol.for('jest')]: expect.any(String)},
  ],
+ [{a: 'b'}, {toString: jestExpect.any(Function)}],
  ]);
 
  [

packages/expect/src/__tests__/utils.test.ts

@@ -11,7 +11,6 @@ import {
  emptyObject,
  getObjectSubset,
  getPath,
- hasOwnProperty,
  iterableEquality,
  subsetEquality,
 } from '../utils';
@@ -107,46 +106,6 @@ describe('getPath()', () => {
  });
 });
 
-describe('hasOwnProperty', () => {
- it('does inherit getter from class', () => {
- class MyClass {
- get key() {
- return 'value';
- }
- }
- expect(hasOwnProperty(new MyClass(), 'key')).toBe(true);
- });
-
- it('does not inherit setter from class', () => {
- class MyClass {
- set key(_value: unknown) {}
- }
- expect(hasOwnProperty(new MyClass(), 'key')).toBe(false);
- });
-
- it('does not inherit method from class', () => {
- class MyClass {
- key() {}
- }
- expect(hasOwnProperty(new MyClass(), 'key')).toBe(false);
- });
-
- it('does not inherit property from constructor prototype', () => {
- function MyClass() {}
- MyClass.prototype.key = 'value';
- // @ts-expect-error
- expect(hasOwnProperty(new MyClass(), 'key')).toBe(false);
- });
-
- it('does not inherit __proto__ getter from Object', () => {
- expect(hasOwnProperty({}, '__proto__')).toBe(false);
- });
-
- it('does not inherit toString method from Object', () => {
- expect(hasOwnProperty({}, 'toString')).toBe(false);
- });
-});
-
 describe('getObjectSubset', () => {
  [
  [{a: 'b', c: 'd'}, {a: 'd'}, {a: 'b'}],

packages/expect/src/utils.ts

@@ -21,33 +21,23 @@ type GetPath = {
  value?: unknown;
 };
 
-// Return whether object instance inherits getter from its class.
-const hasGetterFromConstructor = (object: object, key: string) => {
- const constructor = object.constructor;
- if (constructor === Object) {
- // A literal object has Object as constructor.
- // Therefore, it cannot inherit application-specific getters.
- // Furthermore, Object has __proto__ getter which is not relevant.
- // Array, Boolean, Number, String constructors don’t have any getters.
- return false;
- }
- if (typeof constructor !== 'function') {
- // Object.create(null) constructs object with no constructor nor prototype.
- // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/create#Custom_and_Null_objects
+/**
+ * Checks if `hasOwnProperty(object, key)` up the prototype chain, stopping at `Object.prototype`.
+ */
+const hasPropertyInObject = (object: object, key: string): boolean => {
+ const shouldTerminate =
+ !object || typeof object !== 'object' || object === Object.prototype;
+
+ if (shouldTerminate) {
  return false;
  }
 
- const descriptor = Object.getOwnPropertyDescriptor(
- constructor.prototype,
- key,
+ return (
+ Object.prototype.hasOwnProperty.call(object, key) ||
+ hasPropertyInObject(Object.getPrototypeOf(object), key)
  );
- return descriptor !== undefined && typeof descriptor.get === 'function';
 };
 
-export const hasOwnProperty = (object: object, key: string): boolean =>
- Object.prototype.hasOwnProperty.call(object, key) ||
- hasGetterFromConstructor(object, key);
-
 export const getPath = (
  object: Record<string, any>,
  propertyPath: string | Array<string>,
@@ -129,7 +119,7 @@ export const getObjectSubset = (
  seenReferences.set(object, trimmed);
 
  Object.keys(object)
- .filter(key => hasOwnProperty(subset, key))
+ .filter(key => hasPropertyInObject(subset, key))
  .forEach(key => {
  trimmed[key] = seenReferences.has(object[key])
  ? seenReferences.get(object[key])
@@ -299,7 +289,7 @@ export const subsetEquality = (
  }
  const result =
  object != null &&
- hasOwnProperty(object, key) &&
+ hasPropertyInObject(object, key) &&
  equals(object[key], subset[key], [
  iterableEquality,
  subsetEqualityWithContext(seenReferences),