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

Run details:

User agent: Mozilla/5.0 (Linux; Android 8.1.0; Pixel 2 XL Build/OPM2.171026.006.H1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.100 Mobile Safari/537.36

Browser: Chrome Mobile 69

Operating system: Android 8.1.0

Device Platform: Mobile

Date tested: 5 years ago

Test name	Executions per second
undefined	1781158.0 Ops/sec
typeof	5518187.0 Ops/sec
in	5123279.0 Ops/sec
hasOwnProperty	5027996.0 Ops/sec
bool	5613552.0 Ops/sec

Script Preparation code:

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

Tests:

undefined
undefined !== obj.d;
typeof
'undefined' !== typeof obj.d;
in
'd' in obj;
hasOwnProperty
obj.hasOwnProperty( 'd' );
bool
!! obj.d;

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

Object lookup performance

undefined

typeof

in

hasOwnProperty

bool