Benchmark: isArray vs instanceOf vs Symbol.iterator vs Object.prototype.toString.call.slice

Script Preparation code:

var types = {
  array: [1,2,3],
  number: 123,
  string: '123',
  map: new Map([[1,1],[2,2],[3,3]]),
  set: new Set([1,2,3]),
  buffer: new ArrayBuffer([1,2,3]),
  boolean: true,
  arrow: () => {},
  function: function () {},
  object: {},
  u8: new Uint8Array(),
  u16: new Uint16Array(),
  u32: new Uint32Array(),
  i8: new Int8Array(),
  i16: new Int16Array(),
  i32: new Int32Array()
}

var keys = Object.keys(types)

Tests:

isArray
keys.map(key => Array.isArray(types[key]) === true)
instanceof
keys.map(key => (types[key] instanceof Array) === true)
Symbol.iterator
keys.map(key => types[key][Symbol.iterator] !== undefined)
Object.prototype.toString.call
keys.map(key => Object.prototype.toString.call(types[key]).slice(8, -1) == 'Array')

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
isArray
instanceof
Symbol.iterator
Object.prototype.toString.call

Fastest: N/A

Slowest: N/A

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Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/94.0.4606.71 Safari/537.36 Edg/94.0.992.38

Browser/OS: Chrome 94 on Windows

View result in a separate tab

Test name	Executions per second
isArray	145145.9 Ops/sec
instanceof	139957.8 Ops/sec
Symbol.iterator	87368.4 Ops/sec
Object.prototype.toString.call	94209.5 Ops/sec

isArray vs instanceOf vs Symbol.iterator vs Object.prototype.toString.call.slice (version: 0)

Symbol.iterator also matches TypedArray, Map, and such

Comparing performance of: isArray vs instanceof vs Symbol.iterator vs Object.prototype.toString.call

Created: 2 years ago by: Guest

Jump to the latest result

isArray

instanceof

Symbol.iterator

Object.prototype.toString.call

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A