javascript - 构造函数风格的银行余额工具

Question

我正在尝试构建一个构造函数......一个简单的银行余额概述。

这是我的代码:

class BankAccount {
  constructor(amount = 0) {
    this.toal = amount;
  }
  balance(amount) {
    return this.amount
  }

  withdraw(amount) {
    this.amount - amount;
    return this.amount
  }

  deposit(amount) {
    this.amount + amount;
    return this.amount
  }
}

这就是我所期望的示例。

// Example

var account = new bankAccount(10)
account.withdraw(2)
account.withdraw(5)
account.deposit(4)
account.deposit(1)
account.balance() // 8

它不起作用。我哪里有错误？

Answer 1

有一些错误 - 在 var account = newbankAccount(10) 中，类名称为 BankAccount。

在构造函数中，您将 amount 分配给 this.total，稍后您将使用 this.amount，它不是类成员。而是将其分配给 this.amount。

平衡方法不需要参数balance(amount) --> balance()。

在withdraw方法中，您正在扣除参数传递的金额，但最终结果应存储在this.amount中。 this.amount = this.amount - amount;。与deposit方法类似。

class BankAccount {
  constructor(amount = 0) {
    this.amount = amount;
  }
  balance() {
    return this.amount
  }

  withdraw(amount) {
    this.amount = this.amount - amount;
    return this.amount
  }

  deposit(amount) {
    this.amount = this.amount + amount;
    return this.amount
  }
}

var account = new BankAccount(10)
account.withdraw(2)
account.withdraw(5)
account.deposit(4)
account.deposit(1)
console.log(account.balance()) // 8