Run results for: startsWith vs regex 2

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.0.0 Safari/537.36

Browser: Chrome 122

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 11 months ago

Test name	Executions per second
startsWith	4963087.5 Ops/sec
equals and startsWith	5404366.0 Ops/sec
regex	4355446.5 Ops/sec

Script Preparation code:

var obj = {
  	__protot__: '__protot__',
	_prefixA: '_prefixA',
  	_prefixB: '_prefixB',
  	_prefixC: '_prefixC',
  	_prefixD: '_prefixD',
  	prefixA: '_prefixA',
  	prefixB: '_prefixB',
  	prefixC: '_prefixC',
  	prefixD: '_prefixD',
}

Tests:

startsWith
var count = 0 for (const key of Object.keys(obj)) { if (key.startsWith('__') || key.startsWith('_prefix')) count++ }
equals and startsWith
var count = 0 for (const key of Object.keys(obj)) { if (key === '__protot__' || key.startsWith('_prefix')) count++ }
regex
var count = 0 for (const key of Object.keys(obj)) { if (/^_(_|prefix)/.test(key)) count++ }

Run results for: startsWith vs regex 2

startsWith

equals and startsWith

regex