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)

Working with Functions

In Chapter 1, Introducing TypeScript, we learned the basics of functions. Functions are the fundamental building blocks of any application in TypeScript, and they are powerful enough to deserve the dedication of an entire chapter to explore their potential.

In this chapter, we are going to learn how to work with functions in depth. The chapter is divided into two main sections. The first section starts with a quick recap of some basic concepts, and then moves on to some less commonly known features of functions and their use cases. The first section covers the following concepts:

  • Function declarations and function expressions
  • Function types
  • Functions with optional parameters
  • Functions with default parameters
  • Functions with REST parameters
  • Function overloading
  • Specialized overloading signatures
  • Function scope
  • Immediately invoked functions
  • Tag functions...