Run results for: Plain object check: Object.prototype.toString vs Object.getPrototypeOf

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36

Browser: Chrome 120

Operating system: Windows

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
Object.prototype.toString	16.3 Ops/sec
Object.getPrototypeOf	14.7 Ops/sec

Script Preparation code:

var PLAIN_OBJECT_PROTO = Object.getPrototypeOf({})
var obj = {
  'a': 1,
  'b': 1,
  'c': 1,
  'd': 1,
  'e': 1,
  'f': 1,
  'g': 1
};

Tests:

Object.prototype.toString
for (let i=10000; i > 0; i--) { console.log(Object.prototype.toString.call(obj) === '[object Object]' ? 'P' : 'F'); }
Object.getPrototypeOf
for (let i=10000; i > 0; i--) { console.log(obj !== null && typeof obj === 'object' && Object.getPrototypeOf(obj) === PLAIN_OBJECT_PROTO ? 'P' : 'F') }