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 problem, you need to implement a factory `ToyFactory` that can create a  toy `duck` and a toy `car` object using either the `ToyDuck` or `ToyCar` function constructor. 



A `ToyDuck` object should have the following properties:

* `color`

* `price`

A `ToyCar` object should have the following properties:

* `color`

* `price`

* `name`


As you can see in **line 2**, by default, the `toy` is of `ToyDuck` class.

```
this.toy = ToyDuck;
```

 

>Your task is to create a function, `createToy`.  It should decide which `toy` to create depending on the parameter passed to it. 


## Input

`createToy` function called with different parameters

## Output

Toy duck or car object created depending on the inputs

## Sample input

```
var toyFactory = new ToyFactory();
var car = toyFactory.createToy({
            toyType : "car",
            color: "blue",
            price : 12,
            name : "honda"
})
```

## Sample output

```
ToyCar { color: 'blue', price: 12, name: 'honda' }
```

# Problem statement

In this problem, you need to implement a factory `ToyFactory` that can create a  toy `duck` and a toy `car` object using either the `ToyDuck` or `ToyCar` function constructor. 



A `ToyDuck` object should have the following properties:

* `color`

* `price`

A `ToyCar` object should have the following properties:

* `color`

* `price`

* `name`


As you can see in **line 2**, by default, the `toy` is of `ToyDuck` class.

```
this.toy = ToyDuck;
```

 

>Your task is to create a function, `createToy`.  It should decide which `toy` to create depending on the parameter passed to it. 


# Input

`createToy` function called with different parameters

# Output

Toy duck or car object created depending on the inputs

# Sample input

```
var toyFactory = new ToyFactory();
var car = toyFactory.createToy({
            toyType : "car",
            color: "blue",
            price : 12,
            name : "honda"
})
```

# Sample output

```
ToyCar { color: 'blue', price: 12, name: 'honda' }
```

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

Before We Begin

Introduction To Design Patterns

Creational Patterns

Structural Patterns

Behavioral Patterns

Architectural Patterns

Conclusion

Challenge: Factory Pattern

Problem statement