Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

JavaScript JavaScript and the DOM (Retiring) Traversing the DOM Using previousElementSibling and insertBefore

Nikola Jankovic
Nikola Jankovic
10,793 Points
Posted by Nikola Jankovic
Nikola Jankovic
10,793 Points

Why this alternative solution won't work?

I am just curious why this code instead of the one in the video won't work?

if (event.target.className=== "up" && event.target.parentNode !== listUl.firstChild) {  
        let li = event.target.parentNode;
        let previousLi= li.previousElementSibling;
        let ul = li.parentNode;
        ul.insertBefore(li, previousLi);
    }

1 Answer

Steven Parker
Steven Parker
231,271 Points
Steven Parker
Steven Parker
231,271 Points

The "firstChild" might not be an element, which would interfere with your test.

Try using "firstElementChild" instead.

Nikola Jankovic
Nikola Jankovic
10,793 Points
Nikola Jankovic
Nikola Jankovic
10,793 Points

Yeah, that solves it. Thanks!