Run results for: Private vs public class field access

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/137.0.0.0 Safari/537.36

Browser: Chrome 137

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: one year ago

Benchmark engine: Benchmark.js

Public field access

269.5M/s

Private field access

258.3M/s

View exact numbers

Test name	Executions per second
✓ Public field access	269,506,016 Ops/sec
Private field access	258,287,264 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