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/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36 Edg/120.0.0.0

Browser: Chrome 120

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 2 years ago

cached Intl.NumberFormat instance

1.3M/s

new Intl.NumberFormat

30K/s

Number.prototype.toLocaleString

29K/s

View exact numbers

Test name	Executions per second
✓ cached Intl.NumberFormat instance	1,318,516 Ops/sec
new Intl.NumberFormat	29,768 Ops/sec
Number.prototype.toLocaleString	29,362 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' });