Book Image

Learning TypeScript 2.x - Second Edition

By : Remo H. Jansen
Book Image

Learning TypeScript 2.x - Second Edition

By: Remo H. Jansen

Overview of this book

TypeScript is an open source and cross-platform statically typed superset of JavaScript that compiles to plain JavaScript and runs in any browser or host. This book is a step-by-step guide that will take you through the use and benefits of TypeScript with the help of practical examples. You will start off by understanding the basics as well as the new features of TypeScript 2.x. Then, you will learn how to work with functions and asynchronous programming APIs. You will continue by learning how to resolve runtime issues and how to implement TypeScript applications using the Object-oriented programming (OOP) and functional programming (FP) paradigms. Later, you will automate your development workflow with the help of tools such as Webpack. Towards the end of this book, you will delve into some real-world scenarios by implementing some full-stack TypeScript applications with Node.js, React and Angular as well as how to optimize and test them. Finally, you will be introduced to the internal APIs of the TypeScript compiler, and you will learn how to create custom code analysis tools.
Table of Contents (17 chapters)

Interfaces

Interfaces are probably the feature that you will miss the most while developing large-scale web applications with JavaScript if you have a background in object-oriented statically-typed programming languages such as Java or C#.

Traditionally, in OOP, we say that a class can extend only one class and implement one or more interfaces. An interface can implement one or more interfaces and cannot extend another class or interface. Wikipedia's definition of interfaces in OOP is as follows:

"In object-oriented languages, the term interface is often used to define an abstract type that contains no data or code, but defines behaviors as method signatures."

In TypeScript, interfaces don't strictly follow this definition. The two main differences are that in TypeScript:

  • An interface can extend a class
  • An interface can define data and behaviors as opposed...