fix(helpers): resolveObjectKey returns wrong value for Object.prototype keys

[contactjawad]

What

resolveObjectKey returns an incorrect value (or throws) when the key name collides with an Object.prototype member such as toString, hasOwnProperty, valueOf, isPrototypeOf, __proto__, etc.

Why

The module-level resolver cache keyResolvers was created as a plain object literal, so it inherits from Object.prototype. The cache-miss check

const resolver = keyResolvers[key] || (keyResolvers[key] = _getKeyResolver(key));

sees the inherited prototype method as a truthy value for any such key, and never builds the correct resolver. That inherited function is then invoked as resolver(obj), producing garbage (e.g. toString called with the wrong this returns '[object Undefined]') or throwing (__proto__ is not callable).

How

Make the cache prototype-free by creating it with Object.create(null). Keys that match Object.prototype members now miss the cache and fall through to _getKeyResolver, which builds the correct literal path resolver. Existing '', x, and y fast-paths are unchanged.

Test

Added a case under the resolveObjectKey describe block asserting own properties named after prototype members resolve to their real values:

expect(helpers.resolveObjectKey({toString: 5}, 'toString')).toEqual(5);
expect(helpers.resolveObjectKey({hasOwnProperty: 42}, 'hasOwnProperty')).toEqual(42);
expect(helpers.resolveObjectKey({valueOf: 7}, 'valueOf')).toEqual(7);

Before the fix the first assertion fails with '[object Undefined]' to equal 5; after the fix all pass.