如何识别数组 <{}> 的 javascript 对象字段的类型

Question

我有一个 JavaScript 对象，它来自一个可能包含嵌套字段的请求，我需要识别属于 Array<{}> 类型的字段，我需要单独迭代该字段，但在 javascript 中我无法实现这一点。任何人都请建议我根据字段类型查找字段的解决方案。样本对象const obj = {name:'jane', age: 22,interested_books:[{book_name:'xxx', author_name:'yyy'}, {book_name:'aaa', author_name:'zzz'}],hobbies:['reading', 'football'],address:{street_name:'dace street', door_no:12}}在这些字段中，我需要迭代一个数组<{}>的字段（即interested_books）

Answer 1

使用 Object.entires()andisArray检查它是否是一个数组

obj = {

  name: "jane",

  age: 22,

  interested_books: [

    { book_name: "xxx", author_name: "yyy" },

    { book_name: "aaa", author_name: "zzz" },

  ],

  hobbies: ["reading", "football"],

  address: { street_name: "dace street", door_no: 12 },

};

function getArrWithOb(obj) {

  return Object.fromEntries(

Object.entries(obj).filter((o) => {

  if (Array.isArray(o[1])) {

    if (o[1].every((ob) => typeof ob == "object")) {

      return o;

    }

  }

})

  );

}

console.log(getArrWithOb(obj));

从评论看来你想要返回的是你可以使用的属性的名称reduce

obj = { name: "jane", age: 22, interested_books: [ { book_name: "xxx", author_name: "yyy" }, { book_name: "aaa", author_name: "zzz" }, ], hobbies: ["reading", "football"], address: { street_name: "dace street", door_no: 12 }, };

function getArrWithOb(obj) {

  return Object.entries(obj).reduce((r, o) => {

    if (Array.isArray(o[1])) {

      if (o[1].every((ob) => typeof ob == "object")) {

        r.push(o[0]);

      }

    }

    return r;

  }, []);

}

console.log(getArrWithOb(obj));

Answer 2

使用isArray检查值是否为数组

const obj = {

  name: 'jane',

  age: 22,

  interested_books: [{

    book_name: 'xxx',

    author_name: 'yyy'

  }, {

    book_name: 'aaa',

    author_name: 'zzz'

  }],

  hobbies: ['reading', 'football'],

  address: {

    street_name: 'dace street',

    door_no: 12

  }

}

for (let keys in obj) {

  if (Array.isArray(obj[keys])) {

    obj[keys].forEach(item => console.log(item))

  }

}

Answer 3

const obj = {

  name: 'jane',

  age: 22,

  interested_books: [{

    book_name: 'xxx',

    author_name: 'yyy'

  }, {

    book_name: 'aaa',

    author_name: 'zzz'

  }],

  hobbies: ['reading', 'football'],

  address: {

    street_name: 'dace street',

    door_no: 12

  }

}

for (const key in obj) {

  if (obj[key] instanceof Array) {

    console.log('I am array', key);

    const isArrayOfObject = obj[key].every(item => typeof item === "object");

    if (isArrayOfObject) {

      // your_logic_here

    }

  }

}

Answer 4

试试下面的功能。这是为了获取对象中的数组项。

const obj = {

  name: 'jane',

  age: 22,

  interested_books: [{ book_name: 'xxx', author_name: 'yyy' }, { book_name: 'aaa', author_name: 'zzz' }],

  hobbies: ['reading', 'football'],

  address: { street_name: 'dace street', door_no: 12 }

};

const getArraysFromObject = obj => {

  const results = {};

  Object.keys(obj).map(field => {

    if (Array.isArray(obj[field])) {

      results[field] = obj[field];

    }

  });

  return results;

};

console.log(results); 

// {

//   "interested_books": [

//     { "book_name": "xxx", "author_name": "yyy" },

//     { "book_name": "aaa", "author_name": "zzz" }

//   ],

//   "hobbies": ["reading", "football"]

// }