javascript - 如何对json数组求和

Question

如何使用 jQuery 对这样的 JSON 数组的元素求和：

"taxes": [ 
    { "amount": 25, "currencyCode": "USD", "decimalPlaces": 0, "taxCode": "YRI" },
    { "amount": 25, "currencyCode": "USD", "decimalPlaces": 0, "taxCode": "YRI" },
    { "amount": 10, "currencyCode": "USD", "decimalPlaces": 0, "taxCode": "YRI" }
]

结果应该是：

totalTaxes = 60

Answer 1

使用 JSON 101

var foo = {
        taxes: [
            { amount: 25, currencyCode: "USD", decimalPlaces: 0, taxCode: "YRI"},
            { amount: 25, currencyCode: "USD", decimalPlaces: 0, taxCode: "YRI"},
            { amount: 10, currencyCode: "USD", decimalPlaces: 0, taxCode: "YRI"}
        ]
    },
    total = 0,  //set a variable that holds our total
    taxes = foo.taxes,  //reference the element in the "JSON" aka object literal we want
    i;
for (i = 0; i < taxes.length; i++) {  //loop through the array
    total += taxes[i].amount;  //Do the math!
}
console.log(total);  //display the result

Answer 2

如果你真的必须使用 jQuery，你可以这样做：

var totalTaxes = 0;

$.each(taxes, function () {
    totalTaxes += this.amount;
});

或者您可以在支持它的浏览器中使用 ES5reduce功能：

totalTaxes = taxes.reduce(function (sum, tax) {
    return sum + tax.amount;
}, 0);

或者简单地使用@epascarello的答案中的for循环......