Run results for: Custom Event vs Callback

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 18_1_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/18.1.1 Mobile/15E148 Safari/604.1

Browser: Mobile Safari 18

Operating system: iOS 18.1.1

Device Platform: Mobile

Date tested: one year ago

Custom Event

5K/s

Callback

2K/s

View exact numbers

Test name	Executions per second
✓ Custom Event	5,400 Ops/sec
Callback	2,070 Ops/sec

Tests:

Custom Event
let i = 1001; const results = []; while (--i) { window.dispatchEvent(new CustomEvent('custom:test')); }
Callback
function cb() { console.log('hi') } let i = 1001; const results = []; while (--i) { cb(); }