javascript - 如何返回对象数组属性的总和而不是它们的 double ？

Question

我正在制作一个费用跟踪器基本代码(没有 ui，只有初始脚本)，但是我在尝试 console.log 用户总花费的总和时遇到了问题，我的代码只会将花费的钱加倍对于每件购买的元素，所以我决定在这里寻求帮助。

代码:

//initial code

const account = {
    name: 'user',
    expenses: [],
    addExpense: function(description, amount) {
        account.expenses.push({
            description: description,
            amount: amount
        });
    },
    getAccountSummary: function() {
        let expenses = account.expenses;
        for (let i = 0; i < expenses.length; i++ ) {
            let value = expenses[i].amount + expenses[i].amount;
            console.log(value);
        }
    }
}

//output calls

account.addExpense('Milk', 8);
account.addExpense('Netflix', 30);
account.addExpense('Steam summer sale', 26);
account.addExpense('Coffee', 4);
console.log(account.getAccountSummary());

代码总是在下面记录这个值:

16
60
52
8

实际上是输入值的两倍(8、30、26、4)。

我正在寻找的输出是所有这些值的总和，在这种情况下:

68

希望我的问题很清楚。

Answer 1

如果您想要一个基于数组中项目的值，那么您应该查看 reduce

const account = {
    name: 'user',
    expenses: [],
    addExpense: function(description, amount) {
        account.expenses.push({
            description: description,
            amount: amount
        });
    },
    getAccountSummary: function() {
       return account.expenses.reduce((acc,{amount}) => acc+amount,0);
    }
}