Run results for: isArray

Run details:

User agent: Mozilla/5.0 (Windows NT 6.2; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.117 Safari/537.36

Browser: Chrome 66

Operating system: Windows 8

Device Platform: Other

Date tested: 6 years ago

Test name	Executions per second
Array.isArray	4644563.5 Ops/sec
instanceof	1603919.8 Ops/sec
[].constructor	1691230.4 Ops/sec
Object.prototype.toString	2454445.2 Ops/sec

Script Preparation code:

var toStr = Object.prototype.toString
	
function toStrCase(obj){
  return toStr.call(obj) === '[object Array]'
}
function consCase(obj){
  return obj && obj.constructor === Array
}
function instCase(obj){
  return obj && obj instanceof Array
}
var isArray = Array.isArray

Tests:

Array.isArray
isArray([])
instanceof
instCase([])
[].constructor
consCase([])
Object.prototype.toString
toStrCase([])

Array.isArray vs Object.prototype.toString vs [].constructor vs instanceof

Array.isArray

instanceof

[].constructor

Object.prototype.toString