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/114.0.0.0 Safari/537.36

Browser: Chrome 114

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
typeof x === "undefined"	5908587.5 Ops/sec
x === undefined	2084321.9 Ops/sec
x == undefined	1982623.5 Ops/sec
x == null	6287063.5 Ops/sec
!x	6331705.0 Ops/sec

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