Run results for: Private vs public class field access

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36 Edg/141.0.0.0

Browser: Chrome 141

Operating system: Windows

Device Platform: Desktop

Date tested: 11 months ago

Benchmark engine: Benchmark.js

Public field access

185.3M/s

Private field access

175.7M/s

View exact numbers

Test name	Executions per second
✓ Public field access	185,255,296 Ops/sec
Private field access	175,741,824 Ops/sec

Script Preparation code:

class ClassWithPublicFields {
  a;
  b;
  constructor() {
    this.a = 4;
    this.b = this.a + 3;
  }
}
window.ClassWithPublicFields = ClassWithPublicFields;

class ClassWithPrivateFields {
  #a;
  #b;
  constructor() {
    this.#a = 4;
    this.#b = this.#a + 3;
  }
}
window.ClassWithPrivateFields = ClassWithPrivateFields;

Tests:

Public field access
new ClassWithPublicFields();
Private field access
new ClassWithPrivateFields();

Run results for: Private vs public class field access

This benchmark works in latest Chrome. It will not run in Firefox, until Firefox version 90, which should come out soon.

Public field access

Private field access