Challenge: Flyweight Pattern

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

We'll cover the following

Problem statement #

In this challenge, you have been given the Dress class.

First, you need to define the dressPrice function, which is used to set the price of a dress and return it. The prices of different types of dresses are as follows:

  • maxi: 1000

  • gown: 2000

  • skirt: 500

Every dress has a unique serialNumber, and there cannot be multiple dresses with the same serialNumber. However, in the code given below, there is no such restriction. It allows dresses with the same serialNumber to be created more than once:

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class Dress{
  constructor(serialNumber,type,color,designer,availability){
    this.serialNumber = serialNumber
    this.type = type
    this.color = color
    this.designer = designer
    this.availability = availability
    this.price = 0
  }
  dressPrice(){
    //define
  }
}
const pinkdress1 = new Dress("#123","skirt","pink","Zara","yes")
const pinkdress2 = new Dress("#123","skirt","pink","Zara","yes")
console.log(pinkdress1 === pinkdress2)

As you can see, line 17 returns false, meaning two dresses with the same serialNumber exist. You need to implement the flyweight pattern such that the condition

console.log(pinkdress1 === pinkdress2)

evaluates to true. Here is how you can achieve this:

  • Implement a DressFactory class which has a createDress function. The function definition should not allow different instances of the same serialNumber dress to be created.

Input

Two dresses with the same serialNumber created and dressPrice function called on them

Output

Both the instances should be the same, and the price for both should be returned

Sample input

const factory = new DressFactory()
const pinkdress1 = factory.createDress("#123","skirt","pink","Zara","yes")
const pinkdress2 = factory.createDress("#123","skirt","pink","Zara","yes")

console.log(pinkdress1 === pinkdress2)
console.log(pinkdress1.dressPrice())
console.log(pinkdress2.dressPrice())

Sample output

true
500
500

Challenge #

Take a close look and design a step-by-step solution before jumping on to the implementation. This problem is designed for your practice, so try to solve it on your own first. If you get stuck, you can always refer to the solution provided. Good Luck!

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class Dress{
  constructor(serialNumber,type,color,designer,availability){
    this.serialNumber = serialNumber
    this.type = type
    this.color = color
    this.designer = designer
    this.availability = availability
    this.price = 0
  }
  dressPrice(){
    //define
  }
}

Let’s discuss the solution in the next lesson.