javascript-如何将json数组展平为特定json属性的数组？

Question

所以说我有一个像这样的数组

[ 
    {name: "a", happyName: "bob" }
    , {name: "b", happyName: "cow" }
    , {name: "c", happyName: "moo" }
    , {name: "d", happyName: "jen" }
]

将其展平为数组的最有效方法是：

[ "a","b","c","d"]

（或替代地，仅获取值中的happyName-确切地说，我想我如何将某个给定数组展平为某个给定命名json属性的数组？）

注意，这仅是javascript，请不要使用JQuery等。

Answer 1

这是map()好用例：

var names = theArray.map(function(item) {
    return item.name;
});

var happyNames = theArray.map(function(item) {
    return item.happyName;
});

如果您需要做很多事情，创建一个助手很容易：

var names = values(theArray, 'name'),
    happyNames = values(theArray, 'happyName');

function values(arr, attr) {
    return arr.map(function(item) {
        return item[attr];
    });
}

Answer 2

您可以使用Array.map

var names = arr.map(function(obj) {
    return obj.name;
});

小提琴

Answer 3

var arr = [ 
 {name: "a", happyName: "bob" }
 , {name: "b", happyName: "cow" }
 , {name: "c", happyName: "moo" }
 , {name: "d", happyName: "jen" }
]

var names = arr.map(function(e) { return e.name } )

Answer 4

.map()是一种很酷的方法，但是请记住，它与旧版IE（<9）不兼容。 如果您想要在任何地方都能使用的东西，请执行以下操作：

var arrayOfObjects = [ 
    {name: "a", happyName: "bob" },
    {name: "b", happyName: "cow" },
    {name: "c", happyName: "moo" },
    {name: "d", happyName: "jen" }
],
array = [],
i = 0,
len = arrayOfObjects.length;

for(;i<len;i++) {
    array.push(arrayOfObjects[i].name);
}

// output => [ "a","b","c","d"]