Run results for: new Intl.DateTimeFormat vs cached Intl.DateTimeFormat

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.0 Safari/605.1.15

Browser: Safari 17

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
new Intl.DateTimeFormat.format()	11380.9 Ops/sec
cached Intl.DateTimeFormat.format()	575705.0 Ops/sec
new Intl.DateTimeFormat.formatToParts	11237.4 Ops/sec
cached Intl.DateTimeFormat.formatToParts()	389241.4 Ops/sec

Script Preparation code:

const TWO_DIGIT = '2-digit';

var options = {
      month: TWO_DIGIT,
      year: 'numeric',
      day: TWO_DIGIT,
      hour: TWO_DIGIT,
      hour12: false,
      minute: TWO_DIGIT,
      second: TWO_DIGIT,
    }

var cached = new Intl.DateTimeFormat('en-US', options);

Tests:

new Intl.DateTimeFormat.format()
new Intl.DateTimeFormat('en-US', options).format(new Date());
cached Intl.DateTimeFormat.format()
cached.format(new Date());
new Intl.DateTimeFormat.formatToParts
new Intl.DateTimeFormat('en-US', options).formatToParts(new Date());
cached Intl.DateTimeFormat.formatToParts()
cached.formatToParts(new Date());

Run results for: new Intl.DateTimeFormat vs cached Intl.DateTimeFormat

measure the perf impact of caching calls to new Intl.DateTimeFormat

new Intl.DateTimeFormat.format()

cached Intl.DateTimeFormat.format()

new Intl.DateTimeFormat.formatToParts

cached Intl.DateTimeFormat.formatToParts()