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

Posted by syalih
syalih
16,468 Points

JavaScript .push() TypeError: undefined is not a function

var name = ['math','john']; name.push('alice');

when I try to run this code I face this issue "TypeError: undefined is not a function "

1 Answer

Marcus Parsons
Marcus Parsons
15,719 Points

Hey again Syalih,

When you are initializing var name you are actually pushing the values from the array into window.name which changes the name of the window. And when you try to push new values into name it is not allowing you to do that because name is still a reference to window.name which is a string, not an array.

To get around this, use another variable such as "names". Try to stay away from words that are too generic such as just "id" or "name" as they will likely be keywords in JavaScript. This works perfectly:

var names = ['math','john']; 
names.push('alice');
syalih
syalih
16,468 Points

Thank You :)

Marcus Parsons
Marcus Parsons
15,719 Points

You're very welcome, Syalih! Happy Coding! :)