JSFiddle - React, Tailwind, and code Playground

by uedatakuya

HTML

<div>
    <input id="count" value="1000000" />
    <button id="start">start</button>
</div>Result
<ul>
    <li>for: <span id="for">-</span>ms</li>
    <li>forEach: <span id="foreach">-</span>ms</li>
</ul>

JavaScript

document.querySelector('#start').addEventListener('click', function () {
    var count = parseInt(document.querySelector('#count').value, 10);
    
    var arry = new Array(count);
    
    for (var i = 0; i < count; i++) {
        arry[i] = i;
    }
    
    var hoge = 0;
    
        now = new Date().getTime();
    arry.forEach(function() {
        hoge = 0;
    });
     var time = new Date().getTime() - now;
    document.querySelector('#foreach').innerText = time;

    var now = new Date().getTime();
    for (var i = 0; i < arry.length; i++) {
       arry[i] = i;
    }
    var time = new Date().getTime() - now;
    document.querySelector('#for').innerText = time;
    
}, false);