In this chapter, we will start working with TypeScript, the language Google recommends for using with Angular. All the features ECMAScript 2015 and ECMAScript 2016 provide, such as functions, classes, modules, and decorators, are already implemented in or added to the roadmap of TypeScript. Because of the extra type annotations, there are some syntactical additions compared to JavaScript.

For a smoother transition from the language which is fully supported by modern browsers at the time of writing, that is, ES5, we will start with some common features between ES2016 and TypeScript. Where there are differences between the ES2016 syntax and TypeScript, we'll explicitly mention it. In the second half of the chapter, we'll add the type annotations to everything we've learned until this point.

Later in this chapter, we will explain the extra features TypeScript provides, such as static typing and extra syntax. We will discuss the different consequences based on...