Run results for: undefined vs. typeof vs. in vs. hasOwnProperty - MeasureThat.net

Run details:

User agent: Mozilla/5.0 (Windows NT 5.1; rv:50.0) Gecko/20100101 Firefox/50.0

Browser: Firefox 50

Operating system: Windows XP

Device Platform: Other

Date tested: 7 years ago

Test name	Executions per second
undefined	34087900.0 Ops/sec
typeof	62769600.0 Ops/sec
in	3223641.0 Ops/sec
hasOwnProperty	3975638.0 Ops/sec
truthy	62038120.0 Ops/sec
local undef	42979560.0 Ops/sec

Website performance monitoring

Script Preparation code:

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

Tests:

undefined
undefined !== obj.d;
typeof
'undefined' !== typeof obj.d;
in
'd' in obj;
hasOwnProperty
obj.hasOwnProperty( 'd' );
truthy
!! obj.d;
local undef
undef !== obj.d;