Benchmark: 1000 x event listeners vs single event listener with array of 1000 callbacks

Tests:

1000 event listeners
let i = 1001; const results = []; while (--i) { const index = i; window.addEventListener('custom:test', () => { results.push(index); }, {once: true}); } window.dispatchEvent(new CustomEvent('custom:test'));
1 event listener handling an array of 1000 callbacks
let i = 1001; const results = []; const callbacks = []; while (--i) { const index = i; callbacks.push(() => { results.push(index); }) } window.addEventListener('custom:test', () => { callbacks.forEach((cb) => { cb() }) }, {once: true}); window.dispatchEvent(new CustomEvent('custom:test'));

Rendered benchmark preparation results:

Previous results

Test case name	Result
1000 event listeners
1 event listener handling an array of 1000 callbacks

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Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/112.0.0.0 Safari/537.36

Browser/OS: Chrome 112 on Mac OS X 10.15.7

Test name	Executions per second
1000 event listeners	363.8 Ops/sec
1 event listener handling an array of 1000 callbacks	25999.4 Ops/sec

1000 x event listeners vs single event listener with array of 1000 callbacks (version: 0)