Run results for: detecting if var is instance of class

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/109.0.0.0 Safari/537.36

Browser: Chrome 109

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
instanceof	69844.6 Ops/sec
prop test	71144.2 Ops/sec

Tests:

instanceof

class NewError extends Error {
  constructor() {
    super()
    this.customProp = 'blah'
  }

  customProp
}

const testErr = new NewError()

testErr instanceof NewError

​x
 
class NewError extends Error {  constructor() {    super()    this.customProp = 'blah'  }​  customProp}​const testErr = new NewError()​testErr instanceof NewError

prop test

class NewError extends Error {
  constructor() {
    super()
    this.customProp = 'blah'
  }

  customProp
}

const testErr = new NewError()

!!testErr && typeof testErr === 'object' && 'customProp' in testErr

 
class NewError extends Error {  constructor() {    super()    this.customProp = 'blah'  }​  customProp}​const testErr = new NewError()​!!testErr && typeof testErr === 'object' && 'customProp' in testErr