Suggestion of fix for #7937

jestjs · Feb 19, 2019 · 4afb8dd · 4afb8dd
1 parent 8a2ea1e
commit 4afb8dd
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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.js b/packages/expect/src/utils.js
@@ -251,7 +251,10 @@ export const sparseArrayEquality = (a: any, b: any) => {
   // 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>(