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

# Problem statement

In this challenge, you need to use the mediator pattern to implement the HR of an office that mediates between the employees (workers and managers) of a company.


You have been given the dummy code for the `HR` class. You need to define its `constructor` and the functions:

* `registerEmployee(employee)`: Registers an employee

* `scheduleRaise(raise, worker, manager)`: Conveys the raise to the manager. Once the manager approves the raise, it gives the raise to the worker

Now, let's look at the `Manager` and `Worker` classes. Both of them inherit from the `Employee` class (already defined for you). You need to do the following:

* Define the `constructor` for both classes

* In `Manager` class, define the `receiveMessage` function. It should display the message received from the HR regarding the salary raise of the worker

* In `Manager` class, define the `approveRaise` function. It should display a message of approval of the raise and return true after approval

* In the `Worker` class, define the `receiveRaise` function. It should increment the worker's pay by the raise and display a message for the new pay

# Input

The `scheduleRaise` function is called

# Output

The messages conveying the raise to the manager, manager approving the raise, and the final pay are displayed

# Sample input
```
var hr = new HR()
var employee = new Worker(hr,"Joe","Developer",1400)
var manager = new Manager(hr,"Allen","Team Lead",3000)
hr.scheduleRaise(200,employee,manager)
```

# Sample output
```
"Joe should get 200 dollar raise" //HR conveying the message to the manager
"Joe's 200 dollar raise is approved" //manager approving the raise
"My new pay is 1600 dollars" //worker announcing the new pay
```

In this challenge, you have to implement the mediator pattern to solve the given problem.

Before We Begin

Introduction To Design Patterns

Creational Patterns

Structural Patterns

Behavioral Patterns

Architectural Patterns

Conclusion

Challenge: Mediator Pattern

Problem statement