Suggestion of fix for jestjs#7937

dubzzz · Feb 20, 2019 · d9dfdb3 · d9dfdb3
1 parent be2703c
commit d9dfdb3
Show file tree

Hide file tree

Showing 2 changed files with 8 additions and 1 deletion.
diff --git a/packages/expect/src/__tests__/matchers.test.js b/packages/expect/src/__tests__/matchers.test.js
@@ -281,6 +281,10 @@ describe('.toStrictEqual()', () => {
     }).not.toStrictEqual({b: 2});
   });
 
+  it('does not ignore keys with undefined values inside an array', () => {
+    expect([{a: undefined}]).not.toStrictEqual([{}]);
+  });
+
   it('passes when comparing same type', () => {
     expect({
       test: new TestClassA(1, 2),

diff --git a/packages/expect/src/utils.ts b/packages/expect/src/utils.ts
@@ -256,7 +256,10 @@ export const sparseArrayEquality = (a: unknown, b: unknown) => {
   // A sparse array [, , 1] will have keys ["2"] whereas [undefined, undefined, 1] will have keys ["0", "1", "2"]
   const aKeys = Object.keys(a);
   const bKeys = Object.keys(b);
-  return equals(a, b) && equals(aKeys, bKeys);
+  return (
+    equals(a, b, [iterableEquality, typeEquality], true) &&
+    equals(aKeys, bKeys)
+  );
 };
 
 export const partition = <T>(