使用 lodash 访问对象

Question

我正在尝试使用 indexOf 在如下所示的数组中查找键const areaCode = [    {        "area_code": 656,        "city": "city1"    },    {        "area_code": 220,        "city": "city2"    },    {        "area_code": 221,        "city": "city3"    }]export default areaCode然后我试图根据 area_code 号码获取城市名称const code = inputlet found = indexOf(areaCode, ["area_code", code]);const city = areaCode[found].city但是发现是-1，我做错了什么？

Answer 1

你应该使用 Lodash _.find 函数。

它会是这样的：

const areaCode = [

{

    "area_code": 656,

    "city": "city1"

},

{

    "area_code": 220,

    "city": "city2"

},

{

    "area_code": 221,

    "city": "city3"

}]

const code = input;

const found = _.find(areaCode, function(a){ return a.area_code == code });

console.log(found.city)

const found 将保存匹配区域。

https://lodash.com/docs/4.17.15#find

Answer 2

我相信_.findIndex()

let found = findIndex(areaCode, ["area_code", code]);

Answer 3

根据文档_.indexOf将执行SameValueZero比较来定位索引。简而言之，因为indexOf(data, item)它会尝试使用===to compareitem与data.

相反，您可以使用which accepts将被接受的_.findIndex常用简写：_.matchesProperty_.iteratee

const { findIndex } = _;

const areaCode = [

    {

        "area_code": 656,

        "city": "city1"

    },

    {

        "area_code": 220,

        "city": "city2"

    },

    {

        "area_code": 221,

        "city": "city3"

    }]

const code = 220;

let found = findIndex(areaCode, ["area_code", code]);

console.log("index:", found);

const city = areaCode[found].city

console.log("city:", city);

<script src="https://cdn.jsdelivr.net/npm/lodash@4.17.20/lodash.min.js"></script>

虽然，鉴于您的用法，您可能想要_.find

const { find } = _;

const areaCode = [

    {

        "area_code": 656,

        "city": "city1"

    },

    {

        "area_code": 220,

        "city": "city2"

    },

    {

        "area_code": 221,

        "city": "city3"

    }]

const code = 220;

let found = find(areaCode, ["area_code", code]);

console.log("index:", found);

const city = found.city

console.log("city:", city);

<script src="https://cdn.jsdelivr.net/npm/lodash@4.17.20/lodash.min.js"></script>