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 React Components (2018) Managing State and Data Flow Adding Items to State

Posted by Richard Primas
Richard Primas
415 Points

For some reason I'm receiving an error that states: 'this.state.players.map' is not a function. Any ideas?

It compiles successfully.

1 Answer

Steven Parker
Steven Parker
229,744 Points
Steven Parker
Steven Parker
229,744 Points

To enable a precise answer, always show your code or provide a link to a repo or snapshot.

But generally, that message would indicate that the item you are calling a method ("map") on did not get set to an object of the type you are expecting it to be. Quite often it will contain null or be undefined.

So in this case, I would check to see what this.state.players contains.