Am I the only one having bought this book?

The game 'Alien Invasion' presented in the first chapter contains an error.
In engine.js this.setupInput adds two event handlers.

In both handlers the event parameter is named 'e', although it is referenced as 'event' in both function bodies. Renaming all those references to 'e' solves all problems.


The error is present in the downloadable source too!
This is why almost all example sources of the first three chapters wont work, since you can't start the game.

Good catch - unfortunately with the typo the code continued to work in Chrome and IE (but not Firefox) as they set a global window.event property.

But yes, the "event" variable should be switched to the parameter "e"