Book Image

Hands-On TypeScript for C# and .NET Core Developers

By : Francesco Abbruzzese
5 (1)
Book Image

Hands-On TypeScript for C# and .NET Core Developers

5 (1)
By: Francesco Abbruzzese

Overview of this book

Writing clean, object-oriented code in JavaScript gets trickier and complex as the size of the project grows. This is where Typescript comes into the picture; it lets you write pure object-oriented code with ease, giving it the upper hand over JavaScript. This book introduces you to basic TypeScript concepts by gradually modifying standard JavaScript code, which makes learning TypeScript easy for C# ASP.NET developers. As you progress through the chapters, you'll cover object programming concepts, such as classes, interfaces, and generics, and understand how they are related to, and similar in, both ES6 and C#. You will also learn how to use bundlers like WebPack to package your code and other resources. The book explains all concepts using practical examples of ASP.NET Core projects, and reusable TypeScript libraries. Finally, you'll explore the features that TypeScript inherits from either ES6 or C#, or both of them, such as Symbols, Iterables, Promises, and Decorators. By the end of the book, you'll be able to apply all TypeScript concepts to understand the Angular framework better, and you'll have become comfortable with the way in which modules, components, and services are defined and used in Angular. You'll also have gained a good understanding of all the features included in the Angular/ASP.NET Core Visual Studio project template.
Table of Contents (16 chapters)

Writing declaration files

TypeScript declaration files were introduced in the Declaration files and JavaScript libraries section of Chapter 3, DOM Manipulation, as a way to describe types of libraries that are only available in JavaScript. That section covered where to find them and how to use them. This section, instead, gives some more details on how to write them in case they are not already available somewhere.

The rule of thumb for deciding how to declare entities in declaration file is as follows:

Declarations contain just the structure of objects without the code that implements their behavior. Declarations of entities that require memory allocation must be preceded by the declare keyword.

Type aliases are declared as they are, since they are already pure declarations:

type size = "small"|"average"|"large";

Since interfaces do not contain...