Run results for: instanceof vs manual checking

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/133.0.0.0 Safari/537.36

Browser: Chrome 133

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

extender instanceof Extender

127.8M/s

objBase check property

123.8M/s

base instanceof Extender

118.7M/s

extender instanceof Base

115.2M/s

objExtender check property

113.9M/s

base instanceof Base

113.8M/s

View exact numbers

Test name	Executions per second
✓ extender instanceof Extender	127,838,376 Ops/sec
objBase check property	123,774,040 Ops/sec
base instanceof Extender	118,679,016 Ops/sec
extender instanceof Base	115,179,872 Ops/sec
objExtender check property	113,899,272 Ops/sec
base instanceof Base	113,808,528 Ops/sec

Script Preparation code:

class Base {
   constructor() {
     this.a = 123; 
   }
  
   doSomething() {
     console.log(this.a); 
   }
}

class Extender extends Base {
 	constructor() {
      super();
      this.b = 345;
    }
}

const objBase = new Base();
const objExt = new Extender();

Tests:

base instanceof Base
objBase instanceof Base
extender instanceof Base
objExt instanceof Base
base instanceof Extender
objBase instanceof Extender
extender instanceof Extender
objExt instanceof Extender
objBase check property
!!objBase.b
objExtender check property
!!objExt.b