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

Composite pattern

Composite is a pattern that offers an alternative way to define hierarchies of objects without using inheritance. Again, you want a pattern that avoids inheritance as much as possible because inheritance has many drawbacks in practice. This is one more case against it.

One analogy of this pattern is a company having different types of employee roles, forming a pyramid. Each person is an employee but they have different responsibilities and you can traverse the hierarchy from top to bottom. Using Composite, you want to define objects similar in nature and type, but without attaching too much business logic and behavior to each of them. You want to allow the clients to decide what to perform with this composition of objects. This allows the clients to treat all objects in the hierarchy uniformly.

When to use Composite

There are many reasons why you want to use this pattern and we especially recommend the following ones:

  • To represent a hierarchical model...