javascript - 从对象数组中获取特定数据并转换为对象

Question

我有一个对象数组。在每个对象中也是另一个数组。

结构：

function getData() {
  return [
    {
      _id: 1,
      tags: ["tomato", "butter", "milk"],
      title: "How to make soup?",
      category: "Food"
    },
    {
      _id: 2,
      tags: ["pepper", "salt", "basil"],
       title: "How to use herbs?",
      category: "Herbs"
    },
  ];
}

我试图从数组中获取：标签和类别。输出应该是：

{
      tags: ["tomato", "butter", "milk"],
      category: "Food"
},
 {
      tags: ["pepper", "salt", "basil"],
      category: "Herbs"
},

我尝试了一些概念，但结果并不如我所愿:(

例如：

function getTagsandCategory() {
  const tags = getData()
    .map(post => {post.tags, post.category});

 console.log(tags);
}

getTagsandCategory(); 
// Output: [undefined, undefined]

或更好（但不幸的是不理想）

 function getTagsandCategory() {
  const tags = getData()
    .map(post => [post.tags, post.category]);

 console.log(tags);
}

getTagsandCategory();
// Output: [["tomato", "butter", "milk"], "Food"]

您有什么想法吗，如何实现？谢谢！

Answer 1

你需要使用Array.prototype.map()

const data = [
    {
      _id: 1,
      tags: ["tomato", "butter", "milk"],
      title: "How to make soup?",
      category: "Food"
    },
    {
      _id: 2,
      tags: ["pepper", "salt", "basil"],
       title: "How to use herbs?",
      category: "Herbs"
    },
  ];
  
  const output = data.map(obj => ({ tags: obj.tags, category: obj.category }));
  
  console.log(output);

Answer 2

缺少键

function getData() {
  return [{_id: 1,tags: ["tomato", "butter", "milk"],title: "How to make soup?",category: "Food"},{_id: 2,tags: ["pepper", "salt", "basil"],title: "How to use herbs?",category: "Herbs"}];
}

function getTagsandCategory() {
  const tags = getData()
    .map(post => ({
      tags: post.tags,
      category: post.category
    }));

  console.log(tags);
}

getTagsandCategory();

解构赋值方法

function getData() {
  return [{_id: 1,tags: ["tomato", "butter", "milk"],title: "How to make soup?",category: "Food"},{_id: 2,tags: ["pepper", "salt", "basil"],title: "How to use herbs?",category: "Herbs"}];
}

function getTagsandCategory() {
  const tags = getData().map(({tags, category}) => ({ tags, category }));
  console.log(tags);
}

getTagsandCategory();

Answer 3

// in single line if you want
console.log(getData().map(({tags,category})=> {return {tags,category}}));

-------------------------------------------------------------------
// if you need more re factoring
function getData() {
  return [{
      _id: 1,
      tags: ["tomato", "butter", "milk"],
      title: "How to make soup?",
      category: "Food"
    },
    {
      _id: 2,
      tags: ["pepper", "salt", "basil"],
      title: "How to use herbs?",
      category: "Herbs"
    },
  ];
}

function splitData({tags,category} = {}) {
  return {
    tags,
    category
  };
}

var arr = [];

getData().forEach(val => arr.push(splitData(val)))
console.log(arr);

Answer 4

只需使用地图和解构即可。

function getData() {
  return [
    {
      _id: 1,
      tags: ["tomato", "butter", "milk"],
      title: "How to make soup?",
      category: "Food"
    },
    {
      _id: 2,
      tags: ["pepper", "salt", "basil"],
       title: "How to use herbs?",
      category: "Herbs"
    },
  ];
}

console.log(getData().map(({tags, category}) => ({tags, category})));