Run results for: isArray

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:121.0) Gecko/20100101 Firefox/121.0

Browser: Firefox 121

Operating system: Mac OS X 10.15

Device Platform: Desktop

Date tested: 2 years ago

Benchmark engine: Benchmark.js

Array.isArray

258.3M/s

[].constructor

123.5M/s

instanceof

90.2M/s

Object.prototype.toString

88.0M/s

View exact numbers

Test name	Executions per second
✓ Array.isArray	258,347,552 Ops/sec
[].constructor	123,512,248 Ops/sec
instanceof	90,192,808 Ops/sec
Object.prototype.toString	88,027,592 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