assert,util: fix sparse array comparison

Comparing sparse arrays did not work properly. That is fixed and
tests were added to verify that everything works as expected.

This had an impact on `util.isDeepStrictEqual()` and
`assert.deepStrictEqual()` and their counterpart
`assert.notDeepStrictEqual()`.

PR-URL: https://github.com/nodejs/node/pull/24749
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Michaël Zasso <targos@protonmail.com>

1 files changed, 1 insertions, 2 deletions

diff --git a/lib/internal/util/comparisons.js b/lib/internal/util/comparisons.js
index 43a8921f65..905946fdee 100644
--- a/lib/internal/util/comparisons.js
+++ b/lib/internal/util/comparisons.js
@@ -558,11 +558,10 @@ function objEquiv(a, b, strict, keys, memos, iterationType) {
       } else {
         // Array is sparse.
         const keysA = objectKeys(a);
-        i++;
         for (; i < keysA.length; i++) {
           const key = keysA[i];
           if (!hasOwnProperty(b, key) ||
-              !innerDeepEqual(a[key], b[i], strict, memos)) {
+              !innerDeepEqual(a[key], b[key], strict, memos)) {
             return false;
           }
         }