Book Image

TypeScript 4 Design Patterns and Best Practices

By : Theofanis Despoudis
Book Image

TypeScript 4 Design Patterns and Best Practices

By: Theofanis Despoudis

Overview of this book

Design patterns are critical armor for every developer to build maintainable apps. TypeScript 4 Design Patterns and Best Practices is a one-stop guide to help you learn design patterns and practices to develop scalable TypeScript applications. It will also serve as handy documentation for future maintainers. This book takes a hands-on approach to help you get up and running with the implementation of TypeScript design patterns and associated methodologies for writing testable code. You'll start by exploring the practical aspects of TypeScript 4 and its new features. The book will then take you through the traditional gang of four (GOF) design patterns in their classic and alternative form and show you how to use them in real-world development projects. Once you've got to grips with traditional design patterns, you'll advance to learning about their functional programming and reactive programming counterparts and how to couple them to deliver better and more idiomatic TypeScript code. By the end of this TypeScript book, you'll be able to efficiently recognize when and how to use the right design patterns in any practical use case and gain the confidence to work on scalable and maintainable TypeScript projects of any size.
Table of Contents (14 chapters)
1
Section 1: Getting Started with TypeScript 4
4
Section 2: Core Design Patterns and Concepts
8
Section 3: Advanced Concepts and Best Practices

Creational design patterns

When you declare interfaces and classes in TypeScript, the compiler takes that information and uses it when performing type checks or other assertions. Then at runtime, when the browser or the server evaluates the code, it creates and manages those objects for the duration of the application life cycle. Sometimes you can create objects at the start of the application, for example, you saw the object creation of the Express.js app in the previous chapter:

const app = express(); 

Other times, you might create objects on the fly using an object descriptor. For example, you saw in Chapter 2, TypeScript Core Principles, how you can create HTML span elements:

const span = document.createElement("span");

Both of these approaches deal with object creation, and more specifically, how to instantiate a type of object and store it somewhere. If you think about that for a minute, then you will realize there are two distinct phases here:

  • Creating...