改变JS中对象的结构

Question

const a = {  0: { country: "france", date:"sfzef"},  1: { country: "italie", date:"ttttt"},  2: { country: "belgique", date:"zzzee"}}let obj = {}for (const property in a) {  obj = {...obj, `${a[property].country}: ${a[property]}`}}我想拥有 ：obj = {  france: { country: "france", date:"sfzef"},  italie: { country: "italie", date:"ttttt"},  belgique: { country: "belgique", date:"zzzee"}}我已经尝试了4个小时，在此先感谢会帮助我的人

Answer 1

你很接近，但是当你需要做一个对象的键/值对时，你正在创建一个字符串。计算密钥可以用方括号围绕密钥完成：

const a = {

  0: { country: "france", date:"sfzef"},

  1: { country: "italie", date:"ttttt"},

  2: { country: "belgique", date:"zzzee"}

}

let obj = {}

for (const property in a) {

  obj = {...obj, [a[property].country]: a[property]}

}

console.log(obj);

如果要避免每次都复制对象，可以这样做：

let obj = {}

for (const property in a) {

  obj[a[property].country] = a[property]

}

Answer 2

替代方法：在(参见MDN )reducer的条目上使用 aObject

const a = {

  0: { country: "france", date:"sfzef"},

  1: { country: "italie", date:"ttttt"},

  2: { country: "belgique", date:"zzzee"}

};

const b = Object.entries(a)

  .reduce( (acc, [key, value]) => ({...acc, [value.country]: value}), {} );

console.log(b);