The ultimate guide to coding interviews: Learn and practice JavaScript design patterns tested by FAANG engineers. Get interview-ready in just a few hours with battle-tested solutions.

If you're an experienced developer, chances are your interviewer won't ask you about language syntax. Instead, they'll focus on things that test your understanding of software architecture, and how capable you are at finding optimized solutions to given problems. 

That’s where a strong understanding of design patterns comes in handy. It's often useful to be able to draw on established patterns instead of reinventing the wheel.

In this course, you will learn how to effectively deploy design patterns to answer interview questions. The course is divided into four sections: Creational Patterns, Structural Patterns, Behavioral Patterns, and Architectural Patterns. Each section has its own set of design patterns which you’ll learn to use through various challenges. 

Every challenge contains a detailed solution explanation. By the end of this course (and with some practice), you will be able to confidently use design patterns to tackle advanced coding interview questions in JavaScript.

JavaScript Design Patterns for Coding Interviews

## What is the command pattern?

The **command pattern** allows encapsulation of the requests or operations into separate objects. It decouples the objects that send requests from the objects responsible for executing those requests. 

Consider an example where the client is accessing the methods of an API directly throughout the application. What will happen if the implementation of that API changes? The change will have to be made everywhere the API is being used. *To avoid this, we could make use of abstraction and separate the objects requesting from those implementing the request*. Now, if a change occurs, only the object making the call will need to change.

# What is the command pattern?

The **command pattern** allows encapsulation of the requests or operations into separate objects. It decouples the objects that send requests from the objects responsible for executing those requests. 

Consider an example where the client is accessing the methods of an API directly throughout the application. What will happen if the implementation of that API changes? The change will have to be made everywhere the API is being used. *To avoid this, we could make use of abstraction and separate the objects requesting from those implementing the request*. Now, if a change occurs, only the object making the call will need to change.

This lesson goes over the command pattern in detail with the aid of a coding example.


Before We Begin

Introduction To Design Patterns

Creational Patterns

Structural Patterns

Behavioral Patterns

Architectural Patterns

Conclusion

Command Pattern

What is the command pattern?