Book Image

TypeScript Design Patterns

By : Vilic Vane
Book Image

TypeScript Design Patterns

By: Vilic Vane

Overview of this book

In programming, there are several problems that occur frequently. To solve these problems, there are various repeatable solutions that are known as design patterns. Design patterns are a great way to improve the efficiency of your programs and improve your productivity. This book is a collection of the most important patterns you need to improve your applications’ performance and your productivity. The journey starts by explaining the current challenges when designing and developing an application and how you can solve these challenges by applying the correct design pattern and best practices. Each pattern is accompanied with rich examples that demonstrate the power of patterns for a range of tasks, from building an application to code testing. We’ll introduce low-level programming concepts to help you write TypeScript code, as well as work with software architecture, best practices, and design aspects.
Table of Contents (15 chapters)
TypeScript Design Patterns
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface

Visitor Pattern


Visitor Pattern provides a uniformed interface for visiting different data or objects while allowing detailed operations in concrete visitors to vary. Visitor Pattern is usually used with composites, and it is widely used for walking through data structures like abstract syntax tree (AST). But to make it easier for those who are not familiar with compiler stuff, we will provide a simpler example.

Consider a DOM-like tree containing multiple elements to render:

[ 
  Text { 
    content: "Hello, " 
  }, 
  BoldText { 
    content: "TypeScript" 
  }, 
  Text { 
    content: "! Popular editors:\n" 
  }, 
  UnorderedList { 
    items: [ 
      ListItem { 
        content: "Visual Studio Code" 
      }, 
      ListItem { 
        content: "Visual Studio" 
      }, 
      ListItem { 
        content: "WebStorm" 
      } 
    ] 
  } 
] 

The rendering result in HTML...