Book Image

Mastering TypeScript 3 - Third Edition

By : Nathan Rozentals
Book Image

Mastering TypeScript 3 - Third Edition

By: Nathan Rozentals

Overview of this book

TypeScript is both a language and a set of tools to generate JavaScript. It was designed by Anders Hejlsberg at Microsoft to help developers write enterprise-scale JavaScript. Starting with an introduction to the TypeScript language, before moving on to basic concepts, each section builds on previous knowledge in an incremental and easy-to-understand way. Advanced and powerful language features are all covered, including asynchronous programming techniques, decorators, and generics. This book explores many modern JavaScript and TypeScript frameworks side by side in order for the reader to learn their respective strengths and weaknesses. It will also thoroughly explore unit and integration testing for each framework. Best-of-breed applications utilize well-known design patterns in order to be scalable, maintainable, and testable. This book explores some of these object-oriented techniques and patterns, and shows real-world implementations. By the end of the book, you will have built a comprehensive, end-to-end web application to show how TypeScript language features, design patterns, and industry best practices can be brought together in a real-world scenario.
Table of Contents (16 chapters)
Free Chapter
TypeScript Tools and Framework Options


A class is a definition of an object, what data it holds, and what operations it can perform. Classes and interfaces form a cornerstone of the principles of object-oriented programming. Let's take a look at a simple class definition:

class SimpleClass { 
    id: number; 
    print() : void { 
        console.log(`SimpleClass.print() called`); 

Here, we have used the class keyword to define a class named SimpleClass, and we have defined this class to have a property named id, and a print function. The id property has been defined as type number. The print function simply logs a message to the console. Note that all we have done here is to define what data this class can hold, and what it can do. If we attempt to compile this code, however, we will generate an error, as follows:

error TS2564: Property 'id' has no initializer and is not definitely...