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 Object-Oriented JavaScript: Challenge Making the Game Interactive moveLeft() and moveRight() Methods Solution

Posted by Patricia Padilla
Patricia Padilla
5,026 Points

Uncaught TypeError: this.activePlayer.activeToken.moveRight is not a function at Game.handleKeydown

Everything goes ok until a press the left arrow and then an uncaught typeError appears: Game.js:57 Uncaught TypeError: this.activePlayer.activeToken.moveRight is not a function at Game.handleKeydown (Game.js:57) at HTMLDocument.<anonymous> (app.js:15) I don't know why it fives me this error. Can anyone help please?

3 Answers

Steven Parker
Steven Parker
231,184 Points
Steven Parker
Steven Parker
231,184 Points

A common generic cause of this error is trying to access an attribute/method on a null or undefined variable. Check the value of "activePlayer" or "activePlayer.activeToken".

If you'd like more specific help, make a snapshot of your workspace and post the link to it here.

Patricia Padilla
Patricia Padilla
5,026 Points
Patricia Padilla
Patricia Padilla
5,026 Points

Thanks Steven, I'll take a look and get it working. :)

Cory Aston
Cory Aston
6,058 Points
Cory Aston
Cory Aston
6,058 Points

In my case I got this error because I forgot to save the Token.js file before I ran the code - so literally that function didn't exist! Duh! Took me a couple minutes to figure out why that wasn't working.