There are many JavaScript books on the market these days, and some of them are very good. However, most of them focus on various aspects of the language itself or using certain frameworks to build JavaScript applications. In this book, we are going to take a different approach and look at the architectural design of creating JavaScript applications based on modules, without the need for third-party frameworks.
Creating a good application is more than just writing good code, it is also about how different pieces of the application work and interact with each other. Another characteristic of a good application is its ability to be easily maintained, scaled and extended as needed. A proper modular design enables us to achieve all such goals in our application seamlessly.
In the beginning of this book, I'll be introducing you to the fundamentals of JavaScript modules and the concepts behind a good modular design. Leveraging these concepts, we'll be building an application together, step-by-step, so we can apply what we learn in practice. I recommend reading the chapters in the sequence that they are presented so you can follow along with ease and observe how our design evolves over time.
I would very much encourage you to develop the application pieces with me, as the intent of this book is to be very hands-on, and I would like you to feel as a member of the development team for this application.
As in the real world, we will be re-factoring our code-base a few times during the development phase, in order to implement the new concepts as they are introduced and improve the quality of our application.
Keep in mind that we will be creating a client-side application, and as such, there is no server-side code involved. Nonetheless, many concepts that we will be covering regarding modules and modular architecture can be applied to server-side applications too.
Also, as this book is an introduction to modular JavaScript application design, we will develop a Proof of concept (POC)-grade application together which can provide a good starting point for your own projects.
I have taken a minimalist approach in the implementation, and as a result, we will be using very few third-party libraries in our development process. Therefore, instead of focusing on studying new libraries and how to work with them, you can focus on the application's architecture instead. Once we create a solid foundation, we can incorporate other libraries into our design as required.
For the purposes of clarity, I have shied away from writing fancy code, so you don't have to spend much time trying to understand the intricacies of the code, as opposed to the big picture and how the pieces fit and work together.
Note that this book is meant for people who have a good understanding of JavaScript language, but would like to learn more about JavaScript client-side application design. If you find yourself having trouble with the language itself, you can always refer to online resources and the JavaScript community. This community consists of many smart and helpful people who can, and will be willing to answer your questions. I, for one, am very grateful to the community for its help in my professional growth over the years.
I hope you'll find the book informative and by seeing the benefits of a modular architecture, will use the concepts presented in this book in your own future projects.
Chapter 1, What Are Modules and Their Advantages?, introduces you to the concept of modules and how they can help us design a robust and scalable application.
Chapter 2, Review of Important JavaScript OOP Concepts, covers an overview of some of the important OOP concepts in JavaScript which are necessary for the design and implementation of the modules in our application.
Chapter 3, Module Design Pattern, introduces a very common pattern in creating modules in JavaScript and shows how this pattern can be implemented.
Chapter 4, Designing Simple Modules, uses the module pattern to create simple modules which work together to form the building blocks of our application.
Chapter 5, Module Augmentation, shows the use of various techniques to add more functionality to our modules so that we can extend their capabilities further.
Chapter 6, Cloning, Inheritance, and Submodules, covers how to create modules based on other modules in our application, as well as some more techniques to enhance our modules.
Chapter 7, Base, Sandbox, and Core Modules, introduces some of the main pieces of our application and demonstrates how to create loose coupling among our application modules.
Chapter 8, Application Implementation – Putting It All Together, shows us how to apply all the concepts that we have learned regarding modular architectural design, in order to implement all the pieces of our application.
Chapter 9, Modular Application Design and Testing, covers how to test our application modules using either plain JavaScript or third-party frameworks.
Chapter 10, Enterprise Grade Modular Design, AMD, CommonJS, and ES6 Modules, introduces different modular formats in JavaScript which can be used to design modules, as well as how modules can be imported and exported in our application using these formats.
You will require any modern browser (IE 9+, Chrome, Safari, Firefox) and any OS that can run a modern browser from the preceding list.
The third-party library required would be jQuery 1.8+.
For the later chapters, the following are the third-party libraries:
Jasmin 2+
Mocha (latest version)
Chai (latest version)
RequireJS (latest version)
If you are an intermediate to advanced JavaScript developer who has an experience of writing JavaScript code, but probably not in a modular portable manner, or you are looking to develop enterprise-level JavaScript applications, then this book is for you.
A basic understanding of JavaScript concepts such as OOP, prototypal inheritance, and closures is expected.
In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.
Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "Notice that I have created a function and called it MyObjDefinition".
A block of code is set as follows:
function doAddition(num1, num2){
return num1 + num2;
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