Replace hasOwnProperty with hasPropertyInObject

jestjs · Aug 21, 2020 · 1dde15b · 1dde15b
1 parent 3467338
commit 1dde15b
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Showing 2 changed files with 5 additions and 70 deletions.
diff --git a/packages/expect/src/__tests__/utils.test.ts b/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'}],

diff --git a/packages/expect/src/utils.ts b/packages/expect/src/utils.ts
@@ -21,7 +21,10 @@ type GetPath = {
   value?: unknown;
 };
 
-const hasPropertyInObject = (object: object, key: string) => {
+/**
+ * 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;
 
@@ -35,33 +38,6 @@ const hasPropertyInObject = (object: object, key: string) => {
   );
 };
 
-// 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
-    return false;
-  }
-
-  const descriptor = Object.getOwnPropertyDescriptor(
-    constructor.prototype,
-    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>,
@@ -143,7 +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])