将 JSON 数组转换为选定键的 JSON 数组答案

【问题标题】：convert JSON Array to selected keys' JSON Array将 JSON 数组转换为选定键的 JSON 数组
【发布时间】：2017-04-04 07:34:31
【问题描述】：

我有一个如下的 JSON 数组：

[{
"id": 1,
"name": "Leanne Graham",
"username": "Bret",
"email": "Sincere@april.biz",
"address": {
  "street":"201 S 4th St.",
  "suite": "Apt. 556",
  "city": "Gwenborough",
  "zipcode": "92998-3874",
  "geo": {
    "lat": "-37.3159",
    "lng": "81.1496"
  }
},
"company": {
  "name": "Romaguera-Crona",
  "catchPhrase": "Multi-layered client-server neural-net",
  "bs": "harness real-time e-markets"
},
"hobbies":[
        {
          "books":"fiction",
          "sports":"football",
          "music":"rock"
        },

        {
          "books":"action",
          "sports":"cricket",
          "music":"jazz"
        },
        {
          "books":"action",
          "sports":"cricket",
          "music":"cool"
        },

]},{
"id":2,
"name": "Leanne Graham",
"username": "Bret",
"email": "Sincere@april.biz",
"address": {
  "street": "Kulas Light",
  "suite": "Apt. 556",
  "city": "Gwenborough",
  "zipcode": "92998-3874",
  "geo": {
    "lat": "-37.3159",
    "lng": "81.1496"
  }
},
"phone": ["1-770-736-8031 x56442", "4087917884", "4089088939"],
"website": "hildegard.org",
"dept":[{"name":"divya", "address":"abc"},{"name":"divya1", "address":"abc1"}],
"hobbies":[
          {
            "books":"fiction",
            "sports":"football",
            "music":"rock"
          },

          {
            "books":"action",
            "sports":"cricket",
            "music":"jazz"
          },
          {
            "books":"action",
            "sports":"cricket",
            "music":"cool"
          },
]}]

我只想在爱好键中使用特定键。假设我只需要 Hobbies key 中的书籍和运动。我怎样才能在 Nodejs 中做到这一点？结果应如下所示：

[{
"id": 1,
"name": "Leanne Graham",
"username": "Bret",
"email": "Sincere@april.biz",
"address": {
  "street":"201 S 4th St.",
  "suite": "Apt. 556",
  "city": "Gwenborough",
  "zipcode": "92998-3874",
  "geo": {
    "lat": "-37.3159",
    "lng": "81.1496"
  }
},
"company": {
  "name": "Romaguera-Crona",
  "catchPhrase": "Multi-layered client-server neural-net",
  "bs": "harness real-time e-markets"
},
"hobbies":[
        {
          "books":"fiction",
          "sports":"football",

        },

        {
          "books":"action",
          "sports":"cricket",

        },
        {
          "books":"action",
          "sports":"cricket",

        },

] },{
"id":2,
"name": "Leanne Graham",
"username": "Bret",
"email": "Sincere@april.biz",
"address": {
  "street": "Kulas Light",
  "suite": "Apt. 556",
  "city": "Gwenborough",
  "zipcode": "92998-3874",
  "geo": {
    "lat": "-37.3159",
    "lng": "81.1496"
  }
},
"phone": ["1-770-736-8031 x56442", "4087917884", "4089088939"],
"website": "hildegard.org",
"dept":[{"name":"divya", "address":"abc"},{"name":"divya1", "address":"abc1"}],
"hobbies":[
          {
            "books":"fiction",
            "sports":"football",

          },

          {
            "books":"action",
            "sports":"cricket",

          },
          {
            "books":"action",
            "sports":"cricket",

          },
]}].

请注意，这只是一个示例。我的输入是一个 JSON 数组和我想要保留的键。此示例的键是“id”、“name”、“hobbies.books”、“hobbies.sports”等。

【问题讨论】：

无论如何，您都需要学习如何访问数组元素和对象属性。这归结为对 JavaScript 基础知识缺乏基本了解。

标签： javascript arrays json node.js underscore.js

【解决方案1】：

鉴于您使用的是节点，我不会重新发明轮子。所以你可以在map 旁边使用类似lodash pick 的函数。例如：

const filteredHobbies = theObject.hobbies.map(item => _.pick(item, ['books', 'sports']))

【讨论】：

【解决方案2】：

您可以使用Array.map()。

hobbies.map(function(hobby) {
    return {
        books: hobby.books,
        sports: hobby.sports,
    }
});

这样做是用你在函数中特别返回的值创建一个新数组。

如果你使用 ES6，你也可以使用粗箭头语法和其他“快捷方式”

hobbies.map((hobby) => ({
    books: hobby.books,
    sports: hobby.sports,
});

只需运行您想要操作的任何数组。假设您的对象名为 json，您的函数将如下所示：

const json = [] // your existing JSON

const filtered = json.map((obj) => ({
    id: obj.id,
    name: obj.name,
    hobbies: obj.hobbies.map((hobby) => ({
        books: hobby.books,
        sports: hobby.sports,
    })),
}));

【讨论】：

感谢您的回答，但问题是我不知道关键名称是爱好。它可以是存储在我的变量中的任何内容。所以我需要通用解决方案，其中我的 JSON 数组在一个变量中，另一个变量或数组包含值 hobbies.books 和 hobbies.sports
如何确定您需要哪些密钥？这是您编造的还是您正在关注的 API？
是的，我有一个外部 API 可以为我提供 json 数据，并且根据用户选择的键，我必须只显示该数据

【解决方案3】：

你可以划分出爱好数组，然后：

for(var h of hobbies) {
    delete h.music;
}

最终的代码可能看起来像这样：

var hob = object.hobbies;
for(var h of hob) {
    delete h.music;
}
object.hobbies = hob;

【讨论】：