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),