Run results for: char index vs charAt() vs slice()

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 17_5 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) CriOS/126.0.6478.153 Mobile/15E148 Safari/604.1

Browser: Chrome Mobile iOS 126

Operating system: iOS 17.5

Device Platform: Mobile

Date tested: 2 years ago

character index

18.3M/s

charAt()

17.6M/s

slice()

17.1M/s

View exact numbers

Test name	Executions per second
✓ character index	18,327,178 Ops/sec
charAt()	17,580,750 Ops/sec
slice()	17,126,896 Ops/sec

Script Preparation code:

var str = 'foo bar baz';
var noop = Function.prototype;

Tests:

character index
if (str[0] == 'f') noop();
charAt()
if (str.charAt(0) == 'f') noop();
slice()
if (str.slice(0, 1) == 'f') noop();

Run results for: char index vs charAt() vs slice()

Compare methods for testing string's beggining character.

character index

charAt()

slice()