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 Callback Functions in JavaScript Introduction to Callback Functions Creating an Anonymous Callback Function

Posted by karunaraina
karunaraina
1,352 Points

In the app.js file, functionRunner executes a callback, log. Convert log in to an anonymous function and pass the anonym

In the app.js file, functionRunner executes a callback, log. Convert log in to an anonymous function and pass the anonymous

app.js 
log( () => console.log("Hello World!"))


functionRunner(log);
index.html 
<!DOCTYPE html>
<html lang="en">
    <head>
        <title></title>
        <link rel='stylesheet' href='styles.css'>
    </head>
    <body>
        <section>
            <p>Open your browser's console to see the results</p>
        </section>
        <script src='runner.js'></script>
        <script src='app.js'></script>
    </body>
</html>
runner.js 
function functionRunner(callback) { 
  callback();
}

1 Answer

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

You're close — you've created an anonymous version of "log", but you placed it as the argument to "log" itself.

The new anonymous function should replace "log" in the call to "functionRunner" instead. Then you can completely remove anything left of the original "log".

ja5on
ja5on
10,338 Points

Steven Parker I have the same problem but i dont understand your solution?