CL 1st Duplicate

by Matthew Vasallo

HTML

<ul id="theList">
    <li>6</li>
    <li>3</li>
    <li>1</li>
    <li>4</li>
    <li>7</li>
    <li>4</li>
    <li>2</li>
    <li>8</li>
    <li>9</li>
    <li>2</li>
</ul>

JavaScript

/*
Write an algorithm that will find the first duplicate in a list on the page.
For example we would return 4, for the list above.
*/

var listOfContents = $('#theList li');
var arrayOfContents = [];
var isDuplicate = false;
//alert(listOfContents);

for (var i=0; i < listOfContents.length; i++){
    //alert(listOfContents[i].innerHTML);
    if (arrayOfContents.indexOf(listOfContents[i].innerHTML) === -1){
     arrayOfContents.push(listOfContents[i].innerHTML);   
    }
    else {
       alert(listOfContents[i].innerHTML);
        isDuplicate = true;
        return;
    }
   
}

if (!isDuplicate){
    alert(-1);
}