Run results for: startsWith vs str[0] === char

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 17_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) CriOS/120.0.6099.101 Mobile/15E148 Safari/604.1

Browser: Chrome Mobile iOS 120

Operating system: iOS 17.1

Device Platform: Mobile

Date tested: 2 years ago

Test name	Executions per second
.startsWith	1037.8 Ops/sec
str[0]	6792.9 Ops/sec

HTML Preparation code:

<div></div>

Script Preparation code:

window.regex = /^test/;
window.match = 'test';
var data = window.data = [];
const possible = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
var TOTAL_STRINGS = window.TOTAL_STRINGS = 100000;

function makeRandomString(len) {
  var text = "";
  for( var i=0; i < len; i++ ) {
    text += possible.charAt(0);
  }
  return text;
}

while (data.length < TOTAL_STRINGS) {
  data.push(makeRandomString(1));
}

Tests:

.startsWith
var x = 0; var TOTAL_STRINGS = window.TOTAL_STRINGS; var data = window.data; var match = window.match; while (x < TOTAL_STRINGS) { const str = data[x]; match.startsWith(str); x += 1; }
str[0]
var x = 0; var TOTAL_STRINGS = window.TOTAL_STRINGS; var data = window.data; var match = window.match; while (x < TOTAL_STRINGS) { const str = data[x]; match[0] === str[0]; x += 1; }

Run results for: startsWith vs str[0] === char

Testing some things

.startsWith

str[0]