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

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 14_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/14.0 Mobile/15E148 Safari/604.1

Browser: Mobile Safari 14

Operating system: iOS 14.1

Device Platform: Mobile

Date tested: 2 years ago

Test name	Executions per second
undefined	5988571.0 Ops/sec
typeof	17042700.0 Ops/sec
in	17180090.0 Ops/sec
hasOwnProperty	17109430.0 Ops/sec
bool	17040660.0 Ops/sec
Object.prototype.hasOwnProperty	2959091.0 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: