Run results for: Alternate Array.isArray vs instanceof with nonsense - MeasureThat.net

Run details:

User agent: Mozilla/5.0 (Linux; Android 12; DE2118) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/105.0.0.0 Mobile Safari/537.36

Browser: Chrome Mobile 105

Operating system: Android

Device Platform: Mobile

Date tested: 2 years ago

Test name	Executions per second
Instanceof if	727988.6 Ops/sec
Instanceof npe	466704.2 Ops/sec
Instanceof mpe	712120.8 Ops/sec
isArray if	670750.4 Ops/sec
isArray npe	545159.4 Ops/sec
isArray mpe	613199.4 Ops/sec
Length if	1166748.8 Ops/sec
Length npe	730092.0 Ops/sec
Length mpe	1191733.0 Ops/sec

Script Preparation code:

var c = 0, a = Array(10).fill().map((el,i) => i);var c = 0, a = Array(10).fill().map((el,i) => i);

Tests:

Instanceof if
if(a instanceof Array) ++c;
Instanceof npe
c += Number(a instanceof Array);
Instanceof mpe
c += (0 + (a instanceof Array));
isArray if
if(Array.isArray(a)) ++c;
isArray npe
c += Number(Array.isArray(a))
isArray mpe
c += (0 + (Array.isArray(a)));
Length if
if(a.length > -1) ++c;
Length npe
c += Number(a.length > -1);
Length mpe
c += (0 + (a.length > -1));