[mariazuheros]

Summary

compat/has and compat/hasIn use the path key as it comes, so the property access coerces -0 to '0'. lodash converts path keys with its toKey helper, which turns -0 into '-0':

has({ 0: 'a' }, -0);
// es-toolkit: true
// lodash:     false

has({ '-0': 'a' }, -0);
// es-toolkit: false
// lodash:     true

hasIn([1, 2], -0);
// es-toolkit: true
// lodash:     false

The other compat helpers already agree with lodash here because they run their keys through the internal toKey, among them get, set, unset, result, invoke, updateWith, pullAt and matchesProperty. Only has and hasIn skip it.

Fix

Convert each path segment with the existing _internal/toKey helper before the lookup. The sparse index check compares Number(key) now that the key is already a string, and isIndex keeps rejecting '-0', so a negative zero is never treated as an index.

Tests

Added regression cases to both specs for -0 as a plain key, inside an array path and as a deep path segment, together with the 0 case that has to keep working. Checked against lodash 4.17.21 over a matrix of 972 object and path combinations covering own and inherited keys, sparse arrays, arguments objects, strings, symbols, numeric keys and deep paths. That matrix had 28 mismatches before this change and none after it. The es-toolkit/compat bundle size snapshots that pull in has are updated in a separate commit.

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Project	Deployment	Actions	Updated (UTC)
es-toolkit	Ready	Preview	Aug 17, 2026 11:17am