Run results for: undefined vs typeof vs in vs hasOwnProperty vs bool

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser: Chrome 131

Operating system: Windows

Device Platform: Desktop

Date tested: one month ago

Test name	Executions per second
undefined	9955479.0 Ops/sec
typeof	18914318.0 Ops/sec
in	18712574.0 Ops/sec
hasOwnProperty	17650708.0 Ops/sec
bool	18642852.0 Ops/sec
Object.hasOwnProperty	9341534.0 Ops/sec
optional chaining undefined	18910246.0 Ops/sec

Script Preparation code:

var obj = { a: 1, b: 2, c: 3, d: 4, e: 5 };

Tests: