The third event in this series of fortunate events was the release of ECMAScript 2015. ECMAScript is the official name for JavaScript when discussing its standard. Despite the increase in major version releases, the JavaScript language had largely gone on unchanged for many years. This was due to differences between influencing players (who are best left), causing splintered development and stalled progress in evolving the language. 

To summarize, this was a whirlwind tour of the current state of JavaScript and some of its ecosystem. JavaScript's ecosystem is so vast that several books would need to be written to cover it. For instance, we've not even made mention of visualization JavaScript libraries. There are hundreds, if not thousands, of libraries available for JavaScript that you can use for your projects that we can't even hope to begin to cover. However, there is a part of the JavaScript ecosystem that we will absolutely cover: unit testing. You probably know about the importance of unit testing, and have likely written unit tests for server-side code using frameworks such as JUnit, NUnit, RSpec, and others, depending on the programming language you used. However, unit testing is just as important on the client side, and most developers don't do it, even though they may write unit test script for the server side. Well, in Chapter 13, Unit Testing, you will learn how to write unit tests for the client side and, specifically, how to write them to test your Angular application. The two frameworks we'll cover together are Jasmine (a popular unit testing framework) and Karma (a test runner that has plugins for testing frameworks, such as Jasmine).