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

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.103 Safari/537.36 Vivaldi/2.1.1337.47

Browser: Chrome 70

Operating system: Mac OS X 10.12.6

Device Platform: Desktop

Date tested: 5 years ago

Test name	Executions per second
undefined	3195595.2 Ops/sec
typeof	10705889.0 Ops/sec
in	9759285.0 Ops/sec
hasOwnProperty	9338871.0 Ops/sec
bool	10713240.0 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