[使用reduce查找数组内对象的总和

Posted 2021-04-03

我正在尝试从数组中的对象中查找总数，每个对象都有价格和数量，当数组恰好有两个对象时，我可以找到总数，但是对于两个以上的对象，它会产生NaN。

arr = [ { quantity: 1, price: 30 },
{ quantity: 1, price: 40 },
{ quantity: 2, price: 10 },
{ quantity: 1, price: 10 } ]


const reducer = (accumulator, currentValue) => {
    var a = accumulator.quantity * accumulator.price;
    var b = currentValue.quantity * currentValue.price;
    return a + b;
}
console.log(arr.reduce(reducer));  // sum if array contains 2 objects, NaN otherwise.

答案

    let arr = [ 
    { quantity: 1, price: 30 },
    { quantity: 1, price: 40 },
    { quantity: 2, price: 10 },
    { quantity: 1, price: 10 } 
    ]

    let reducer = (acc, cur) => {
     return acc + (Number(cur.quantity) * Number(cur.price));
    };

    console.log(arr.reduce(reducer, 0));
    // 100

另一答案

arr = [ { quantity: 1, price: 30 },
{ quantity: 1, price: 40 },
{ quantity: 2, price: 10 },
{ quantity: 1, price: 10 } ]

const reducer = (accumulator, currentValue) {
    return accumulator + (currentValue.quantity * accumulator.price);
}

console.log(arr.reduce(reducer, 0 ));

另一答案

您可以简单地说