Introducing JavaScript Game Development. Graeme Stuart

This book provides a full set of exercises in which we will build a fully functional HTML canvas game. Though not a direct clone, the game is inspired by the 1979 Atari classic, Asteroids.
The code is provided for you and is introduced piece by piece over the various chapters of the book. If you’d like to try Asteroids, or if you’ve never played it, the the modern Atari version can be played at https://atari.com/arcade#!/arcade/ asteroids/play.
I’ve made a few different gameplay decisions for the game we create in this book, and I encourage you to attempt to adapt the game in any direction you like as we go along, if you feel confident in doing so. It’s all good practice!
Typically, each chapter introduces an area of game design in a generic way, develops the ideas towards implementing an aspect of the Asteroids game, and urges you to think about alternative approaches.
Towards the end of the book, the game will be complete, and you should have all the skills necessary to build a quality game of your own. During most of the exercises, you’re encouraged to be creative.
Go through the material provided, consider the challenges presented, and explore the impact of modifying the provided code.
There’s no “correct” way to design a game like this—it involves making many decisions, and the provided code is only one of thousands of possible ways to do it. So, please, try it your way if you feel confident enough. That’s a great way to learn something.