Run results for: undefined vs. typeof vs. in vs. hasOwnProperty vs Object.prototype.hasOwnProperty

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.88 Safari/537.36

Browser: Chrome 87

Operating system: Windows

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
undefined	4380317.5 Ops/sec
typeof	12740056.0 Ops/sec
in	12891769.0 Ops/sec
hasOwnProperty	11452514.0 Ops/sec
bool	12766004.0 Ops/sec
Object.prototype.hasOwnProperty	2190175.2 Ops/sec

Script Preparation code:

var obj = { a: 1, b: 2, c: 3, d: 4, e: 5 };
function hasOwn (obj, key) {
  return hasOwnProperty.call(obj, key)
}

Tests: