javascript - 使用任何 lodash 获取嵌套 JSON 对象的所有值

Question

场景:我有一个变量 JSON

var json = {
    "order": {
        "orderDetails": [{
            "a1": "b1",
            "c1": "d1",
            "e1": "f1"
        }, {
            "a1": "b2",
            "c1": "d2",
            "e1": "f2"
        }, {
            "a1": "b3",
            "c1": "d3",
            "e1": "f3"
        }],
        "orderHeader": [{
            "a2": "b1",
            "c2": "d1",
            "e2": "f1"
        }, {
            "a2": "b2",
            "c2": "d2",
            "e2": "f2"
        }]
    }
};

我需要获取 order.orderdetails.a1 所有值的数组，例如

['b1', 'b2', 'b3']

Answer 1

因为你 underscore.js , lodash包括在内，为什么不利用它们而不是重新发明轮子。

单行使用_.map怎么样？ . _.map 也接受字符串作为 iteratee 并将从传递的对象返回该键的值。

_.map(json.order.orderDetails, 'a1')

var json = {
    "order": {
        "orderDetails": [{
            "a1": "b1",
            "c1": "d1",
            "e1": "f1"
        }, {
            "a1": "b2",
            "c1": "d2",
            "e1": "f2"
        }, {
            "a1": "b3",
            "c1": "d3",
            "e1": "f3"
        }],
        "orderHeader": [{
            "a2": "b1",
            "c2": "d1",
            "e2": "f1"
        }, {
            "a2": "b2",
            "c2": "d2",
            "e2": "f2"
        }]
    }
};

var result = _.map(json.order.orderDetails, 'a1');

console.log(result);
document.getElementById('result').innerHTML = JSON.stringify(result, 0, 4); // For Demo: Showing the result on the screen

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.0.0/lodash.js"></script>
<pre id="result"></pre>

这类似于 _.pluck在旧版本的 lodash 中。

_.pluck(json.order.orderDetails, 'a1')

---

在纯 JavaScript 中使用 Array#map 可以获得相同的结果。

json.order.orderDetails.map(e => e.a1)

var json = {
    "order": {
        "orderDetails": [{
            "a1": "b1",
            "c1": "d1",
            "e1": "f1"
        }, {
            "a1": "b2",
            "c1": "d2",
            "e1": "f2"
        }, {
            "a1": "b3",
            "c1": "d3",
            "e1": "f3"
        }],
        "orderHeader": [{
            "a2": "b1",
            "c2": "d1",
            "e2": "f1"
        }, {
            "a2": "b2",
            "c2": "d2",
            "e2": "f2"
        }]
    }
};

var result = json.order.orderDetails.map(e => e.a1);
console.log(result);
document.getElementById('result').innerHTML = JSON.stringify(result, 0, 4);

<pre id="result"></pre>