Run results for: What's faster? cached Intl.NumberFormat vs new Intl.NumberFormat vs toLocaleString currency

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/26.0.1 Safari/605.1.15

Browser: Safari 26

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 7 months ago

Test name	Executions per second
cached Intl.NumberFormat instance	2781179.0 Ops/sec
new Intl.NumberFormat	33546.3 Ops/sec
Number.prototype.toLocaleString	33896.3 Ops/sec

Script Preparation code:

window.cachedFormatter = new Intl.NumberFormat('pt-BR', { style: 'currency', currency: 'BRL' });

Tests:

cached Intl.NumberFormat instance
window.cachedFormatter.format(3_950_219.56);
new Intl.NumberFormat
new Intl.NumberFormat('pt-BR', { style: 'currency', currency: 'BRL' }).format(3_950_219.56);
Number.prototype.toLocaleString
(3_950_219.56).toLocaleString('pt-BR', { style: 'currency', currency: 'BRL' });