JavaScript 将对象数组映射到新对象数组的最短方法？

Question

我有一组 person 对象，其中每个 person 都有一组 profiles 对象，其中包含名称和图像 url，以及由 lat 和 long 属性组成的地址对象列表，如下所示:

var listOfPersons = [{
    addresses : [{lat:11, long:11}, {lat:22, long:22}],
    profile: [{image:"some_url1", name: "peter parker"}]
},
{
    addresses : [{lat:33, long:33}, {lat:44, long:44}],
    profile: [{image:"some_url2", name: "bruce wayne"}]
}];

我需要创建一个新的对象数组，其中每个新对象都有一个 image、long、lat 属性，用于 每组 lat long，如下:

var expectedResult = [
{
    image:"some_url1",
  lat:11,
  long:11
},
{
    image:"some_url1",
  lat:22,
  long:22
},
{
    image:"some_url1",
  lat:33,
  long:33
},
{
    image:"some_url1",
  lat:44,
  long:44
}
];

map\reduce 第一个数组到第二个数组的最短方法(就编写代码而言)是什么？

Answer 1

您可以使用嵌套的 Array.flatMap() 和 Array.map() 来迭代数组/地址/配置文件，并组合 image 和 lat、long 属性合并到一个对象中:

const listOfPersons = [{"addresses":[{"lat":11,"long":11},{"lat":22,"long":22}],"profile":[{"image":"some_url1","name":"peter parker"}]},{"addresses":[{"lat":33,"long":33},{"lat":44,"long":44}],"profile":[{"image":"some_url2","name":"bruce wayne"}]}];

const result = listOfPersons.flatMap(o =>
  o.addresses.flatMap(({ lat, long }) => 
    o.profile.map(({ image }) => ({
      image,
      lat,
      long
    }))
  )
);

console.log(result);

如果您始终只使用第一个配置文件，则可以删除一层 Array.flatMap():

const listOfPersons = [{"addresses":[{"lat":11,"long":11},{"lat":22,"long":22}],"profile":[{"image":"some_url1","name":"peter parker"}]},{"addresses":[{"lat":33,"long":33},{"lat":44,"long":44}],"profile":[{"image":"some_url2","name":"bruce wayne"}]}];

const result = listOfPersons.flatMap(o =>
  o.addresses.map(({ lat, long }) =>  ({
    image: o.profile[0].image,
    lat,
    long
  }))
);

console.log(result);