Fix: Symbol based properties in arrays causes toEqual to throw (#6391)

* Fixed issue where jest fails to compare symbol properties in arrays

* Updated changelog

* fixup changelog

* Fixed linting errors

* Supress incorrect flow error

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ### Fixes
 
+- `[expect]` Using symbolic property names in arrays no longer causes the `toEqual` matcher to fail ([#6391](https://github.com/facebook/jest/pull/6391))
 - `[expect]` `toEqual` no longer tries to compare non-enumerable symbolic properties, to be consistent with non-symbolic properties. ([#6398](https://github.com/facebook/jest/pull/6398))
 
 ## 23.1.0

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

@@ -443,6 +443,19 @@ describe('.toEqual()', () => {
     }
   });
 
+  test('symbol based keys in arrays are processed correctly', () => {
+    const mySymbol = Symbol('test');
+    const actual1 = [];
+    actual1[mySymbol] = 3;
+    const actual2 = [];
+    actual2[mySymbol] = 4;
+    const expected = [];
+    expected[mySymbol] = 3;
+
+    expect(actual1).toEqual(expected);
+    expect(actual2).not.toEqual(expected);
+  });
+
   test('non-enumerable members should be skipped during equal', () => {
     const actual = {
       x: 3,

packages/expect/src/jasmine_utils.js

@@ -227,7 +227,8 @@ function keys(obj, isArray, hasKey) {
   }
 
   for (var x = 0; x < allKeys.length; x++) {
-    if (!allKeys[x].match(/^[0-9]+$/)) {
+    //$FlowFixMe
+    if (typeof allKeys[x] === 'symbol' || !allKeys[x].match(/^[0-9]+$/)) {
       extraKeys.push(allKeys[x]);
     }
   }