Run results for: string.split vs string.substring vs toLocaleDateString("pt-PT") vs Intl.DateTimeateTimeFormat

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/134.0.0.0 Safari/537.36 Edg/134.0.0.0

Browser: Chrome 134

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
✓ substring	57,292,552 Ops/sec
slice	19,438,186 Ops/sec
split	8,921,397 Ops/sec
Intl with format cache with date cache	315,600 Ops/sec
Date toLocaleString with date being cached	266,791 Ops/sec
Intl with format cache no date cache	261,353 Ops/sec
Date toLocaleString without date being cached	232,712 Ops/sec
Intl no format cache no date cache	6,039 Ops/sec
Intl no format cache with date cache	5,889 Ops/sec

Test name

Executions per second

✓ substring

57,292,552 Ops/sec

slice

19,438,186 Ops/sec

split

8,921,397 Ops/sec

Intl with format cache with date cache

315,600 Ops/sec

Date toLocaleString with date being cached

266,791 Ops/sec

Intl with format cache no date cache

261,353 Ops/sec

Date toLocaleString without date being cached

232,712 Ops/sec

Intl no format cache no date cache

6,039 Ops/sec

Intl no format cache with date cache

5,889 Ops/sec

Tests:

split
const [yyyy, mm, dd] = dateStr.split("/"); const result =`${dd}/${mm}/${yyyy}`;
Date toLocaleString without date being cached
const result = new Date(dateStr).toLocaleString("pt-PT");
slice
const day = dateStr.slice(8, 10); const month = dateStr.slice(5, 7); const year = dateStr.slice(0, 4); const result = `${day}/${month}/${year}`
substring
const day = dateStr.substring(8, 10); const month = dateStr.substring(5, 7); const year = dateStr.substring(0, 4); const result = `${day}/${month}/${year}`
Intl no format cache no date cache
const result = new Intl.DateTimeFormat("pt-PT").format(new Date(dateStr));
Intl no format cache with date cache
const result = new Intl.DateTimeFormat("pt-PT").format(dateDate);
Intl with format cache no date cache
const result = formatter.format(new Date(dateStr));
Intl with format cache with date cache
const result = formatter.format(dateDate);
Date toLocaleString with date being cached
const result = dateDate.toLocaleString("pt-PT");