Run results for: Undefined testing including ! - MeasureThat.net

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/116.0.0.0 Safari/537.36 OPR/102.0.0.0

Browser: Opera 102

Operating system: Windows

Device Platform: Desktop

Date tested: 8 months ago

Test name	Executions per second
typeof x === "undefined"	13208730.0 Ops/sec
x === undefined	4919502.0 Ops/sec
x == undefined	4981228.0 Ops/sec
x == null	13932450.0 Ops/sec
!x	13954640.0 Ops/sec

Website performance monitoring

Script Preparation code:

var x;

Tests:

typeof x === "undefined"
typeof x === "undefined"
x === undefined
x === undefined
x == undefined
x == undefined
x == null
x == null
!x
!x