Learning JavaScript Design Patterns, 2nd Edition

Chapter 6. Categories of Design Patterns

This chapter documents the three main categories of design patterns and the different patterns that fall under them. While every design pattern addresses a specific object-oriented design problem or issue, we can draw parallels between the solutions based on how they solve these issues. This forms the basis for the categorization of design patterns.

Background

Gamma, Helm, Johnson, and Vlissides (1995), in their book, Design Patterns: Elements of Reusable Object-Oriented Software, describe a design pattern as:

A design pattern names, abstracts, and identifies the key aspects of a common design structure that make it useful for creating a reusable object-oriented design. The design pattern identifies the participating classes and their instances, their roles and collaborations, and the distribution of responsibilities.

Each design pattern focuses on a particular object-oriented design problem or issue. It describes when it applies, whether or not it can be applied in view of other design constraints, and the consequences and trade-offs of its use. Since we must eventually implement our designs, a design pattern also provides sample…​code to illustrate an implementation.

Although design patterns describe object-oriented designs, they are based on practical solutions that have been implemented in mainstream object-oriented programming languages…​.

Design patterns can be categorized based on the type of problem they solve. The three principal ...