Challenge: Command Pattern

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

We'll cover the following

Problem statement #

Study and then run the code below:

class BankAccount {
    constructor(amount){
        this.amount = amount
    }
  checkAmount() {
      console.log(this.amount)
  }
  
  withdrawMoney(withdrawamount) {
    if(withdrawamount > this.amount){
        console.log("Not enough money")
    }
    else{
        this.amount -=  withdrawamount
    }
  }
   depositAmount(money){
        this.amount += money
    }
}
var account = new BankAccount(100)
account.checkAmount()
account.withdrawMoney(10)
account.checkAmount()
account.depositAmount(50)
account.checkAmount()

In the code, you have a BankAccount class. You can check the amount in the account using the checkAccount function. Withdraw a certain amount using the withdrawMoney function and deposit an amount using the depositAmount function.

Your task is to modify the code above by using the command pattern. Remember, the pattern has the following parts:

  • commands: WithDraw, DepositAmount, and CheckAmount.

  • receiver: BankAccount.

  • invoker: an AccountManager carrying out the operations requested using a request function.

Use your knowledge of the pattern to divide your code into these objects.

Input

Sending commands to carry out operations such as withdrawMoney, checkAmount, and depositAmount

Output

The amount in the account after operations are performed

Sample input

const manager = new AccountManager();
const account = new BankAccount(100)
const check = new CheckAmount(account);
manager.request(check)
const withdraw = new WithDrawAmount(account);
const deposit = new DepositAmount(account);
manager.request(withdraw,10)
manager.request(check)
manager.request(deposit,50)
manager.request(check)

Sample output

100
90
140

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!

class BankAccount {
    constructor(amount){
        this.amount = amount
    }
  checkAmount() {
      console.log(this.amount)
  }
  
  withdrawMoney(withdrawamount) {
    if(withdrawamount > this.amount){
        console.log("Not enough money")
    }
    else{
        this.amount -=  withdrawamount
    }
  }
   depositAmount(money){
        this.amount += money
    }
}

Let’s discuss the solution in the next lesson.