Book Image

Test-Driven JavaScript Development

By : Ravi Kumar Gupta
Book Image

Test-Driven JavaScript Development

By: Ravi Kumar Gupta

Overview of this book

Initially, all processing used to happen on the server-side and simple output was the response to web browsers. Nowadays, there are so many JavaScript frameworks and libraries created that help readers to create charts, animations, simulations, and so on. By the time a project finishes or reaches a stable state, so much JavaScript code has already been written that changing and maintaining it further is tedious. Here comes the importance of automated testing and more specifically, developing all that code in a test-driven environment. Test-driven development is a methodology that makes testing the central part of the design process – before writing code developers decide upon the conditions that code must meet to pass a test. The end goal is to help the readers understand the importance and process of using TDD as a part of development. This book starts with the details about test-driven development, its importance, need, and benefits. Later the book introduces popular tools and frameworks like YUI, Karma, QUnit, DalekJS, JsUnit and goes on to utilize Jasmine, Mocha, Karma for advanced concepts like feature detection, server-side testing, and patterns. We are going to understand, write, and run tests, and further debug our programs. The book concludes with best practices in JavaScript testing. By the end of the book, the readers will know why they should test, how to do it most efficiently, and will have a number of versatile tests (and methods for devising new tests) to get to work immediately.
Table of Contents (16 chapters)
Test-Driven JavaScript Development
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Overview


The observer pattern defines a relationship between more than one object where one object is observed by many others. The system is designed in such a way that when a state of the observed object is changed, all observing objects get notified automatically. This pattern is also known as dependents and pub/sub (publication/subscription).

Mainly people like to use the observer pattern in JavaScript, and there are possibilities/chances that people are using it already. We commonly use event handling on DOM elements in all size of application and that can be achieved with the use of observer pattern.

The main and very important feature of the observer pattern is that we can add or remove the observer at runtime. The observer pattern gives an ability to subscribe to an event and then give a notification to the user when the event comes into the picture. With the use of the observer pattern user can get facility of object-oriented design and it also provides loose coupling.

Many different...