I'm getting an error related to 'undefined is not a function'. What does this mean and how can I fix it?

This error usually means you're trying to call something as a function that isn't actually a function. It often happens when you're trying to call a property that's undefined or null. Double-check the spelling of the function name and ensure that the object you're calling it on actually has that function as a property. Also, verify that the function is properly defined and accessible in the current scope.