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

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.1.2 Safari/605.1.15

Browser: Safari 17

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 2 years ago

Benchmark engine: Benchmark.js

str[0]

6K/s

.startsWith

964/s

View exact numbers

Test name	Executions per second
✓ str[0]	6,139 Ops/sec
.startsWith	964 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]