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

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.82 Safari/537.36

Browser: Chrome 89

Operating system: Linux

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
undefined	3200394.0 Ops/sec
typeof	9676214.0 Ops/sec
in	9754986.0 Ops/sec
hasOwnProperty	8885489.0 Ops/sec
truthy	9870796.0 Ops/sec
local undef	4776234.0 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;