javascript找到数组项的父项(javascript find parent of array item)

javascript找到数组项的父项(javascript find parent of array item)

我有一个这样的数组项目：

var array = USA.NY[2]; // gives "Albany" {"USA" : { "NY" : ["New York City", "Long Island", "Albany"] }}

我想从只有阵列中找到状态。 我该怎么做呢？ 谢谢。

function findParent(array) { // do something // return NY }

I have an array item like this:

var array = USA.NY[2]; // gives "Albany" {"USA" : { "NY" : ["New York City", "Long Island", "Albany"] }}

I want to find the state from just having the array. How do I do this? Thanks.

function findParent(array) { // do something // return NY }

最满意答案

在Javascript中，数组元素没有引用包含它们的数组。

为了达到这个目的，你将不得不引用'root'数组，这取决于你的数据模型。 假设美国是可访问的，并且只包含数组，你可以这样做：

function findParent(item) { var member, i, array; for (member in USA) { if (USA.hasOwnProperty(member) && typeof USA[member] === 'object' && USA[member] instanceof Array) { array = USA[member]; for(i = 0; i < array.length; i += 1) { if (array[i] === item) { return array; } } } } }

请注意，我已将array参数重命名为item因为您正在传递一个值（和数组项），并且您期望返回该数组。 如果你想知道数组的名字 ，你应该返回member 。

In Javascript, array elements have no reference to the array(s) containing them.

To achieve this, you will have to have a reference to the 'root' array, which will depend on your data model. Assuming USA is accessible, and contains only arrays, you could do this:

function findParent(item) { var member, i, array; for (member in USA) { if (USA.hasOwnProperty(member) && typeof USA[member] === 'object' && USA[member] instanceof Array) { array = USA[member]; for(i = 0; i < array.length; i += 1) { if (array[i] === item) { return array; } } } } }

Note that I’ve renamed the array parameter to item since you’re passing along a value (and array item), and you expect the array to be returned. If you want to know the name of the array, you should return member instead.