Run results for: overwrite string vs null vs const two

Run details:

User agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.181 Safari/537.36

Browser: Chrome 66

Operating system: Windows 7

Device Platform: Desktop

Date tested: 5 years ago

Test name	Executions per second
isUndefined	2296265.0 Ops/sec
isN	494823000.0 Ops/sec

Tests: