Run results for: Regex vs For loop [1-9]|X

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.5060.134 Safari/537.36

Browser: Chrome 103

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
Regex	4893407.5 Ops/sec
For loop	1370203.0 Ops/sec
For loop with switch case	1102529.4 Ops/sec

Script Preparation code:

var dataPool = ["1234", "1X34", "0123", "12x4"];
var testStr = dataPool[Math.floor(Math.random() * dataPool.length)];
var mwcRegex = /^(?:(?:1|X)(?=2|X|$))(?:(?:2|X)(?=3|X|$))?(?:(?:3|X)(?=4|X|$))?(?:(?:4|X)(?=5|X|$))?(?:(?:5|X)(?=6|X|$))?(?:(?:6|X)(?=7|X|$))?(?:(?:7|X)(?=8|X|$))?(?:(?:8|X)(?=9|X|$))?(?:(?:9|X)$)?$/;

Tests:

Regex and Loop
let isValid = true; for (let i = 0; i < testStr.length; i++) { let code = testStr.charAt(i); let regStr = `(${i+1}|X)`; const regEx = new RegExp(regStr); if(regEx.test(code) === false){ isValid = false; break; } } return isValid;
For loop, ParseInt
let isValid = true; for (let i = 0; i < testStr.length; i++) { let code = testStr.charAt(i); if (code === "X"){ } else{ let codeValue = parseInt(code, 10); if(codeValue !== i+1){ isValid = false; break; } } } return isValid;
For loop with switch case
let isValid = true; for (let i = 0; i < testStr.length; i++) { let char = testStr.charAt(i); switch (true) { case char === 'X': break; case parseInt(char, 10) === i + 1: break; default: isValid = false; } } return isValid;
For loop, toString
let isValid = true; for (let i = 0; i < testStr.length; i++) { let code = testStr.charAt(i); if (code === "X"){ } else{ if(code !== (i+1).toString()){ isValid = false; break; } } } return isValid;
Pure Regex
return mwcRegex.test(testStr);

Run results for: Regex vs For loop [1-9]|X

Regex and Loop

For loop, ParseInt

For loop with switch case

For loop, toString

Pure Regex