expect: Compare DOM nodes even if there are multiple Node classes

CHANGELOG.md

@@ -4,6 +4,8 @@
 
 ### Fixes
 
+- `[expect]` Compare DOM nodes even if there are multiple Node classes ([#8064](https://github.com/facebook/jest/pull/8064))
+
 ### Chore & Maintenance
 
 - `[pretty-format]`: Use `react-is` instead of manual `$$typeof` checks ([#8060](https://github.com/facebook/jest/pull/8060))

packages/expect/src/__tests__/toEqual-dom.test.js

@@ -0,0 +1,218 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @jest-environment jsdom
+ */
+/* eslint-env browser*/
+
+describe('toEqual', () => {
+  describe('duck type', () => {
+    // https://github.com/facebook/jest/issues/7786
+
+    const createElement = (name, ...childNodes) => ({
+      childNodes,
+      nodeType: 1,
+      tagName: name.toUpperCase(),
+    });
+
+    const createTextNode = data => ({
+      data,
+      nodeType: 3,
+    });
+
+    const createDocumentFragment = (...children) => ({
+      children,
+      nodeType: 11,
+    });
+
+    describe('Text', () => {
+      test('isNot false', () => {
+        const data = 'deep equal';
+
+        const a = createTextNode(data);
+        const b = createTextNode(data);
+
+        expect(a).toEqual(b);
+        expect(b).toEqual(a);
+      });
+
+      test('isNot true', () => {
+        const a = createTextNode('not deep equal a');
+        const b = createTextNode('not deep equal b');
+
+        expect(a).not.toEqual(b);
+        expect(b).not.toEqual(a);
+      });
+    });
+
+    describe('Element', () => {
+      test('isNot false', () => {
+        const name = 'span';
+        const data = 'deep equal';
+
+        const a = createElement(name, createTextNode(data));
+        const b = createElement(name, createTextNode(data));
+
+        expect(a).toEqual(b);
+        expect(b).toEqual(a);
+      });
+
+      test('isNot true', () => {
+        const data = 'not deep equal';
+
+        const a = createElement('strong', createTextNode(data));
+        const b = createElement('span', createTextNode(data));
+
+        expect(a).not.toEqual(b);
+        expect(b).not.toEqual(a);
+      });
+    });
+
+    describe('Fragment', () => {
+      test('isNot false', () => {
+        const name1 = 'strong';
+        const name2 = 'span';
+        const data1 = 'deep';
+        const data2 = 'equal';
+
+        const a = createDocumentFragment(
+          createElement(name1, createTextNode(data1)),
+          createElement(name2, createTextNode(data2)),
+        );
+        const b = createDocumentFragment(
+          createElement(name1, createTextNode(data1)),
+          createElement(name2, createTextNode(data2)),
+        );
+
+        expect(a).toEqual(b);
+        expect(b).toEqual(a);
+      });
+
+      test('isNot true', () => {
+        const name = 'span';
+        const data1 = 'not';
+        const data2 = 'deep equal';
+
+        const a = createDocumentFragment(
+          createElement('strong', createTextNode(data1)),
+          createElement(name, createTextNode(data2)),
+        );
+        const b = createDocumentFragment(
+          createElement(name, createTextNode(data1)),
+          createElement(name, createTextNode(data2)),
+        );
+
+        expect(a).not.toEqual(b);
+        expect(b).not.toEqual(a);
+      });
+    });
+  });
+
+  describe('document', () => {
+    describe('createTextNode', () => {
+      test('isNot false', () => {
+        const data = 'deep equal';
+
+        const a = document.createTextNode(data);
+        const b = document.createTextNode(data);
+
+        expect(a).toEqual(b);
+        expect(b).toEqual(a);
+      });
+
+      test('isNot true', () => {
+        const a = document.createTextNode('not deep equal a');
+        const b = document.createTextNode('not deep equal b');
+
+        expect(a).not.toEqual(b);
+        expect(b).not.toEqual(a);
+      });
+    });
+
+    describe('createElement', () => {
+      test('isNot false', () => {
+        const name = 'span';
+        const data = 'deep equal';
+
+        const a = document.createElement(name);
+        const b = document.createElement(name);
+        a.appendChild(document.createTextNode(data));
+        b.appendChild(document.createTextNode(data));
+
+        expect(a).toEqual(b);
+        expect(b).toEqual(a);
+      });
+
+      test('isNot true', () => {
+        const data = 'not deep equal';
+
+        const a = document.createElement('strong');
+        const b = document.createElement('span');
+        a.appendChild(document.createTextNode(data));
+        b.appendChild(document.createTextNode(data));
+
+        expect(a).not.toEqual(b);
+        expect(b).not.toEqual(a);
+      });
+    });
+
+    describe('createDocumentFragment', () => {
+      test('isNot false', () => {
+        const name1 = 'strong';
+        const name2 = 'span';
+        const data1 = 'deep';
+        const data2 = 'equal';
+
+        const aSpan1 = document.createElement(name1);
+        const bSpan1 = document.createElement(name1);
+        aSpan1.appendChild(document.createTextNode(data1));
+        bSpan1.appendChild(document.createTextNode(data1));
+
+        const aSpan2 = document.createElement(name2);
+        const bSpan2 = document.createElement(name2);
+        aSpan2.appendChild(document.createTextNode(data2));
+        bSpan2.appendChild(document.createTextNode(data2));
+
+        const a = document.createDocumentFragment();
+        const b = document.createDocumentFragment();
+        a.appendChild(aSpan1);
+        a.appendChild(aSpan2);
+        b.appendChild(bSpan1);
+        b.appendChild(bSpan2);
+
+        expect(a).toEqual(b);
+        expect(b).toEqual(a);
+      });
+
+      test('isNot true', () => {
+        const name = 'span';
+        const data1 = 'not';
+        const data2 = 'deep equal';
+
+        const aSpan1 = document.createElement('strong');
+        const bSpan1 = document.createElement(name);
+        aSpan1.appendChild(document.createTextNode(data1));
+        bSpan1.appendChild(document.createTextNode(data1));
+
+        const aSpan2 = document.createElement(name);
+        const bSpan2 = document.createElement(name);
+        aSpan2.appendChild(document.createTextNode(data2));
+        bSpan2.appendChild(document.createTextNode(data2));
+
+        const a = document.createDocumentFragment();
+        const b = document.createDocumentFragment();
+        a.appendChild(aSpan1);
+        a.appendChild(aSpan2);
+        b.appendChild(bSpan1);
+        b.appendChild(bSpan2);
+        console.log(a.innerHTML);
+
+        expect(a).not.toEqual(b);
+        expect(b).not.toEqual(a);
+      });
+    });
+  });
+});

packages/expect/src/jasmineUtils.ts

@@ -247,10 +247,14 @@ export function isA(typeName: string, value: unknown) {
   return Object.prototype.toString.apply(value) === '[object ' + typeName + ']';
 }
 
-function isDomNode(obj: any): obj is Node {
-  // In some test environments (e.g. "node") there is no `Node` even though
-  // we might be comparing things that look like DOM nodes.
-  return typeof Node !== 'undefined' && obj instanceof Node;
+function isDomNode(obj: any): boolean {
+  return (
+    obj !== null &&
+    typeof obj === 'object' &&
+    typeof obj.nodeType === 'number' &&
+    typeof obj.nodeName === 'string' &&
+    typeof obj.isEqualNode === 'function'
+  );
 }
 
 export function fnNameFor(func: Function) {