Run results for: instanceof Array vs Array.isArray()

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/117.0.0.0 Safari/537.36

Browser: Chrome 117

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
instanceof Array	3129.2 Ops/sec
Array.isArray()	3208.1 Ops/sec

Script Preparation code:

var arr = new Array(1000).fill(null);
for(let i = 0; i < arr.length; i++) {
	if(i % 3 === 0) {
    	arr[i] = [1];
    } else if(i % 2 === 0) {
    	arr[i] = {a: 1};
    } else {
      arr[i] = '1';
    }
}

Tests:

instanceof Array
let circle = 5; while(circle > 0) { const check = arr.map(item => item instanceof Array); circle--; }
Array.isArray()
let circle = 5; while(circle > 0) { const check = arr.map(item => Array.isArray(item)); circle--; }