Json 数组循环

Question

我正在开发 asp.net 视觉工作室。我正在使用 jquery 调用 web 方法。 在 asp.net 中，我正在创建一个动态数据表。我正在返回 JsonConvert.SerializeObject(dt)；

$.ajax({
    type: 'POST',
    url: 'Default.aspx/GetCustomers',
    dataType: 'json',
    contentType: "application/json; charset=utf-8",
    success: function (result) {

        console.log((result.d));
        cars = result.d;
        $.each(cars, function (index, key) {

            console.log(index);
            console.log(key);

        })

    }
});

这是从asp.net返回的json

[{"Name":"Jones","January 2019":53.0000,"February 2019":33.0000,"March 2019":55.0000 }]

当我遍历它 $.each 时，我得到一个错误

SCRIPT5007：SCRIPT5007：“in”的操作数无效：预期对象

如何访问键和值？

Answer 1

循环通过这个 JSON：

const cars = [{
  "Name": "Jones",
  "January 2019": 53.0000,
  "February 2019": 33.0000,
  "March 2019": 55.0000
}]

// jQuery
$.each(cars, function(index, key) {
  const car = Object.entries(key)
  console.log('$.each()')
  $.each(car, function(i, el) {
    console.log('key:', el[0])
    console.log('val:', el[1])
  })
})

// JavaScript
cars.forEach(e => {
  console.log('forEach()')
  for (let [key, val] of Object.entries(e)) {
    console.log(`key: ${key}`)
    console.log(`val: ${val}`)
  }
})

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

我认为关键是 Object.entries()。

更多关于Object.entries()：https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/entries

Answer 2

另一种方法是使用 Object.Keys，如下所示：

var cars = [
	{
		"Name": "Jones",
		"January 2019": 53.0000,
		"February 2019": 33.0000,
		"March 2019": 55.0000
	}
];

$.each(cars,
	function(index, dict) {

		console.log(index);
		console.log(dict);

		Object.keys(dict)
			.forEach(function eachKey(key) { // or .forEach(function (key) { 
				console.log(key + ': ' + dict[key]); 
			});

	});

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>