Book Image

Opa Application Development

By : Li Wenbo
Book Image

Opa Application Development

By: Li Wenbo

Overview of this book

Opa is a full-stack Open Source web development framework for JavaScript that lets you write secure and scalable web applications. It generates standard Node.js/MongoDB applications, natively supports HTML5 and CSS and automates many aspects of modern web application programming. It handles all aspects of web programming written in one consistent language and compiled to web standards.Opa Application Development is a practical,hands-on guide that provides you with a number of step-by-step exercises. It covers almost all aspects of developing a web application with Opa, which will help you take advantage of the real power of Opa, as well as building a secure, powerful web application rapidly.Opa Application Development dives into all concepts and components required to build a web application with Opa. The first half of this book shows you all of the basic building blocks that you will need to develop an Opa application, including the syntax of Opa, web development aspects, client and server communication and slicing, plugin, database, and so on. By the end of the book you will have yourself created a complete web application along with a game: Pacman!
Table of Contents (18 chapters)
Opa Application Development
About the Author
About the Reviewers

Binding the external JavaScript library

In our Pacman game, we need to preload game resources such as images and sounds. We need to play sounds and music as well. Of course, we could write our own code to accomplish these tasks. However, why reinvent the wheel? There are numerous JavaScript libraries that make our job easier. The following section shows how to bind an existing JavaScript library into our game.

Preloading the resources

When a program requires multiple images and sounds, as is the case with our Pacman game, it's usually a good idea to load all of the resources before displaying or playing them. There are many excellent JavaScript libraries available. For our purposes, the Preload JS 0.3.0 (for resource) and SoundJS 0.4.0 (for sounds) libraries are a good fit. You can download Preload JS 0.3.0 from and the SoundJS 0.4.0 library is available at

To bind the JavaScript library, we must register those functions...