Run results for: JavaScript String Starts/Ends With String Comparisons - Playground

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: 9 months ago

Test name	Executions per second
indexOf at end of sentence v1	3972.0 Ops/sec
indexOf at end of sentence v2	3954.6 Ops/sec
string endsWith	123.9 Ops/sec
Regex match ends with	122.8 Ops/sec
indexOf starts with	3926.6 Ops/sec
search starts with	42.0 Ops/sec
string startsWith	123.7 Ops/sec
Regex match starts with	120.6 Ops/sec

HTML Preparation code:

<div></div>

Script Preparation code:

const iterationNum = 250000;
const possible = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz";
const possibleLen = possible.length;

function getRandomIntInclusive(max, min = 1) {
  const minCeiled = Math.ceil(min);
  const maxFloored = Math.floor(max);
  return Math.floor(Math.random() * (maxFloored - minCeiled + 1) + minCeiled); // The maximum is inclusive and the minimum is inclusive
}

function makeRandomString(len, defaultWord = '') {
  let text = defaultWord;
  for(let i = 0; i < len; i++) {
    text += possible.charAt(getRandomIntInclusive(possibleLen, 0));
  }
  return text + defaultWord;
}

const testWord = window.testWord = makeRandomString(getRandomIntInclusive(10));
const allStrings = window.allStrings = new Array(iterationNum);
const numberOfStrings = window.numberOfStrings = iterationNum;

for(let i = 0; i < numberOfStrings; i++) {
    allStrings[i] = makeRandomString(getRandomIntInclusive(20), testWord);
}

Tests:

indexOf at end of sentence v1
let x = 0; const numberOfStrings = window.numberOfStrings; const allStrings = window.allStrings; const testWord = window.testWord; const testWordLen = testWord.length; while (x < numberOfStrings) { const str = allStrings[x]; str.indexOf(testWord) === str.length - testWordLen; x += 1; }
indexOf at end of sentence v2
let x = 0; const numberOfStrings = window.numberOfStrings; const allStrings = window.allStrings; const testWord = window.testWord; const testWordLen = testWord.length; while (x < numberOfStrings) { const str = allStrings[x]; str.length - str.indexOf(testWord) !== str.length + 1; x += 1; }
string endsWith
let x = 0; const numberOfStrings = window.numberOfStrings; const allStrings = window.allStrings; const testWord = window.testWord; while (x < numberOfStrings) { const str = allStrings[x]; str.endsWith(testWord); x += 1; }
Regex match ends with
let x = 0; const numberOfStrings = window.numberOfStrings; const allStrings = window.allStrings; const testWord = window.testWord; const testWordRegExp = new RegExp(`${testWord}$`); while (x < numberOfStrings) { const str = allStrings[x]; str.match(testWordRegExp); x += 1; }
indexOf starts with
let x = 0; const numberOfStrings = window.numberOfStrings; const allStrings = window.allStrings; const testWord = window.testWord; const testWordLen = testWord.length; while (x < numberOfStrings) { const str = allStrings[x]; str.indexOf(testWord) === 0; x += 1; }
search starts with
let x = 0; const numberOfStrings = window.numberOfStrings; const allStrings = window.allStrings; const testWord = window.testWord; const testWordLen = testWord.length; while (x < numberOfStrings) { const str = allStrings[x]; str.search(testWord) === 0; x += 1; }
string startsWith
let x = 0; const numberOfStrings = window.numberOfStrings; const allStrings = window.allStrings; const testWord = window.testWord; while (x < numberOfStrings) { const str = allStrings[x]; str.startsWith(testWord); x += 1; }
Regex match starts with
let x = 0; const numberOfStrings = window.numberOfStrings; const allStrings = window.allStrings; const testWord = window.testWord; const testWordRegExp = new RegExp(`^${testWord}`); while (x < numberOfStrings) { const str = allStrings[x]; str.match(testWordRegExp); x += 1; }

Run results for: JavaScript String Starts/Ends With String Comparisons - Playground

indexOf at end of sentence v1

indexOf at end of sentence v2

string endsWith

Regex match ends with

indexOf starts with

search starts with

string startsWith

Regex match starts with