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

The Command pattern

The Command pattern deals with creating special request objects that can be passed as parameters to receiver objects. The main idea of this pattern is that you want to separate a request action from handling each request in a way that both the request and receiver objects are decoupled. For instance, say you create an object that contains all the information necessary to perform actions such as triggering notifications or emails. This object will contain information such as the receiver's email address, name, or title. The receiver merely knows how to process the commands and employs the appropriate handler depending on the type of command. This way, you promote the single-responsibility principle, which is part of the SOLID principles, as you separate the responsibilities of the classes that perform actions and the classes that create actions.

An analogy of this pattern is where you have a microwave with buttons that represent actions. When you press a...