Run results for: object property lookup: in operator vs undefined comparison

Run details:

User agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.75 Safari/537.36

Browser: Chrome 68

Operating system: Windows 7

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
in operator	6990547.5 Ops/sec
!==undefined comparison	2352455.0 Ops/sec

Script Preparation code:

var obj={prop:'dddd'};

Tests: