Run results for: Checking for presence of object key - MeasureThat.net

Run details:

User agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:108.0) Gecko/20100101 Firefox/108.0

Browser: Firefox 108

Operating system: Ubuntu

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
in – first element	811561728.0 Ops/sec
in – last element	842012160.0 Ops/sec
typeof – first element	858163776.0 Ops/sec
typeof – last element	840668352.0 Ops/sec
! – first element	865953216.0 Ops/sec
! – last element	861358720.0 Ops/sec

Script Preparation code:

var obj = {
   'first' : 1,
   'is' : 1,
   'some' : 1,
   'nice' : 1,
   'test' : 1,
   'last' : 1
}

Tests:

in – first element
if ('first' in obj) { }
in – last element
if ('last' in obj) { }
typeof – first element
if (typeof obj['first'] !== "undefined") { }
typeof – last element
if (typeof obj['last'] !== "undefined") { }
! – first element
if (!obj['first']) { }
! – last element
if (!obj['last']) { }

;