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

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/101.0.4951.41 Safari/537.36 Edg/101.0.1210.32

Browser: Chrome 101

Operating system: Windows

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
new Intl.DateTimeFormat.format()	8812.1 Ops/sec
cached Intl.DateTimeFormat.format()	297803.6 Ops/sec
new Intl.DateTimeFormat.formatToParts	8857.9 Ops/sec
cached Intl.DateTimeFormat.formatToParts()	144113.9 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()