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

Using interfaces, classes, and inheritance – the Factory Design Pattern

To illustrate how we can use interfaces and classes in a large TypeScript project, we will take a quick look at a very well-known object-oriented design pattern—the Factory Design pattern.

Business requirements

As an example, let's assume that our business analyst gives us the following requirements:

  1. You are required to categorize people, given their date of birth, into three different age groups—Infants, Children, and Adults.
  2. Indicate with a true or false flag whether they are of a legal age to sign a contract.
  3. A person is deemed to be an infant if they are less than two years old.
  4. Infants cannot sign contracts.
  5. A person is...