Run results for: Object key, typeof === 'function' vs startsWith 'on'

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/140.0.0.0 Safari/537.36

Browser: Chrome 140

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 10 months ago

startsWith on

1K/s

typeof key === function

602/s

View exact numbers

Test name	Executions per second
✓ startsWith on	1,043 Ops/sec
typeof key === function	602 Ops/sec

HTML Preparation code:

<!--your preparation HTML code goes here-->

Script Preparation code:

const attrs = {
  class: 'test',
  onclick: e => console.log(e),
  style: 'color: red;',
  onfocus: e => console.log(e),
};
const count = 1000;

Tests:

typeof key === function
for(let i = 0; i < count; i++) { const el = document.createElement('div'); for(const [k, v] of Object.entries(attrs)) { if(typeof k === 'function') el[k] = v; else el.setAttribute(k, v); } }
startsWith on
for(let i = 0; i < count; i++) { const el = document.createElement('div'); for(const [k, v] of Object.entries(attrs)) { if(k.startsWith('on')) el[k] = v; else el.setAttribute(k, v); } }