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 = input

let 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_.iterateeconst { 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].cityconsole.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_.findconst { 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.cityconsole.log("city:", city);<script src="https://cdn.jsdelivr.net/npm/lodash@4.17.20/lodash.min.js"></script>