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

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 16_6 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) CriOS/117.0.5938.108 Mobile/15E148 Safari/604.1

Browser: Chrome Mobile iOS 117

Operating system: iOS 16.6

Device Platform: Mobile

Date tested: one year ago

Test name	Executions per second
new Intl.DateTimeFormat.format()	11478.0 Ops/sec
cached Intl.DateTimeFormat.format()	642212.0 Ops/sec
new Intl.DateTimeFormat.formatToParts	11524.3 Ops/sec
cached Intl.DateTimeFormat.formatToParts()	409608.6 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()