Run results for: One iteration vs two comparable checks

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.0.0 Safari/537.36

Browser: Chrome 124

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
One iteration	0.4 Ops/sec
Two iterations	0.1 Ops/sec

Script Preparation code:

window.a = Array(1_000_000).fill(null).flatMap(() => [1, 2, 3, 4, 5])
window.b = [1, 2, 3, 4, 5]

Tests:

One iteration
for (let i = 0, l = a.length; i < l; i++) { if(b.some(y => (a[i] + y) === 'no')){ break; } if (!b.some(y => a[i] === y)) { break; } }
Two iterations
for (let i = 0, l = a.length; i < l; i++) { if(b.some(y => (a[i] + y) === 'no')){ break; } } for (let i = 0, l = a.length; i < l; i++) { if (!b.some(y => a[i] === y)) { break; } }