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

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/116.0.5845.1077 YaBrowser/23.9.1.1077 Yowser/2.5 Safari/537.36

Browser: Yandex Browser 23

Operating system: Linux

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
undefined	5193888.5 Ops/sec
typeof	17596372.0 Ops/sec
in	17158738.0 Ops/sec
hasOwnProperty	15622645.0 Ops/sec
bool	17662618.0 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