JavaScript将对象数组映射到新对象数组的最短方式？
我有一个person对象数组，其中每个person都有一个由名称和图像url组成的profiles对象数组，以及一个由lat和long属性组成的addresses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，用于集lat long，如下所示：
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
}
];将第一个数组转换为第二个数组的map\ reduce的最短方式(就编写代码而言)是什么？
回答 5
Stack Overflow用户
发布于 2020-01-07 15:26:45
您可以使用嵌套Array.flatMap()和Array.map()来迭代数组/地址/概要文件，并将image和lat、long属性组合到一个对象中：
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);
如果始终只使用第一个配置文件，则可以删除一个级别的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);
Stack Overflow用户
发布于 2020-01-07 15:24:16
您可以将Array.prototype.reduce()与组合Array.prototype.forEach()结合使用。
reduce()的文档状态
()方法对数组的每个元素执行约简函数(您提供的)，从而得到一个单一的输出值。
我认为以下几点对你是有用的：
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.reduce((acc, cur) => {
cur.addresses.forEach(e => acc.push({ ...e, image: cur.profile[0].image }));
return acc;
}, []);
console.log(result);
我希望这能帮上忙！
Stack Overflow用户
发布于 2020-01-07 15:31:53
既然您在编写代码时要求最短：
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"}]}];
const res = listOfPersons.reduce((r,{addresses:a,profile:[{image}]})=> [...r,...a.map(o=>({image,...o}))],[]);
console.log(res);
这里有格式和更好的变量名：
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"}]
}];
const res = listOfPersons.reduce((acc, { addresses: adr, profile: [{image}] }) =>
[...acc, ...adr.map(a => ({image, ...a}) )],
[]);
console.log(res);
https://stackoverflow.com/questions/59631246
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