Before we jump into the technical parts and the code, it would be worthwhile to take a quick look at the evolution of JavaScript, and some of the drivers that led to the need for a language such as a TypeScript. Also, just as Angular's naming jungle caused some confusion in the development community, JavaScript has had an even more confusing versioning past since its inception over two decades ago, and so I'd like to try and clear up some of the confusion around JavaScript's version naming. More importantly, I'd like to cover what I like to refer to as the series of fortunate events for JavaScript. This will help set the pace for much of the material we'll be covering together in the rest of the book.

I must confess, I love working with JavaScript. I have always enjoyed the language—not for the language itself, but because it allowed us to make the web come alive without the need for other plugins, such as Flash or Shockwave. However, in recent years, there are a few additional reasons for why I love working with the language, and the exact reasons I love JavaScript are precisely the series of fortunate events that I will cover shortly. Having said that, I have friends in the industry that are on the other end of the spectrum, who view JavaScript as a toy language, and prefer to remain shackled to languages such as Java and C#, avoiding JavaScript at all costs until they have to grudgingly write some code for the client side. These old-timers' usage of JavaScript typically extends no further than binding a click event to a function call (using the jQuery library) to submit form data to their Java or C# APIs. Sure, about a decade ago, JavaScript wasn't as powerful as Java or C# for a few reasons, such as it was a language that only ran on the client side (that is, on browsers), there were not as many libraries for it, and highly performant runtimes for it did not really exist. All this was about to change due the series of fortunate events—specifically, three of them. Let's review them quickly.