Question

我有这组数据，我无法控制（它在某个地方托管了API，我没有访问权限）

let x = [
    {name: "james", age: 10, school: {id:1, name:"London"}},
    {name: "james_2", age: 11, school: {id:1, name:"London"}},
    {name: "john", age: 12, school: {id:2, name:"India"}},
    {name: "johnny", age: 56, school: {id:3, name:"USA"}}
]

我怎样才能先上学？我需要这样的格式

[{
    id:1,
    name: "London",
    data: [{
        name: "james", age: 10, school: {id:1, name:"London"
    },{name: "james_2", age: 11, school: {id:1, name:"London"}}]
}]

Answer 1

您可以使用_.groupBy()并将结果映射回数组：

const data = [{"name":"james","age":10,"school":{"id":1,"name":"London"}},{"name":"james_2","age":11,"school":{"id":1,"name":"London"}},{"name":"john","age":12,"school":{"id":2,"name":"India"}},{"name":"johnny","age":56,"school":{"id":3,"name":"USA"}}];

const result = _(data)
  .groupBy('school.name')
  .map((group) => ({ // or Object.assign({}, group[0].school, { data: group });
    ...group[0].school,
    data: group
  }))
  .value();

console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script>

将Array#reduce与Map结合使用，您可以在不使用lodash的情况下执行相同的操作：

const data = [{"name":"james","age":10,"school":{"id":1,"name":"London"}},{"name":"james_2","age":11,"school":{"id":1,"name":"London"}},{"name":"john","age":12,"school":{"id":2,"name":"India"}},{"name":"johnny","age":56,"school":{"id":3,"name":"USA"}}];

const result = [...data.reduce((map, item) => {
  const school = map.get(item.school.name) || { // or Object.assign({}, { item.school }, { data: [] })
    ...item.school, data: [] 
  };
  
  school.data.push(item);
  
  map.set(item.school.name, school);
  
  return map;
}, new Map()).values()]

console.log(result);

Answer 2

您可以创建一个哈希对象，以每个学校的ID来存储它，这样您就可以将学生推向它：

var hash=x.reduce(function(obj,el){
 (obj[el.school.id]=obj[el.school.id]||{id:el.school.id,name:el.school.name,data:[]}).data.push({name:el.name,age:el.age});
  return obj;
},{});

var arr=Object.values(hash);

http://jsbin.com/vedajijiye/edit?console

Answer 3

您可以使用reduce()方法：

＆＃13;

let data = [
    {name: "james", age: 10, school: {id:1, name:"London"}},
    {name: "james_2", age: 11, school: {id:1, name:"London"}},
    {name: "john", age: 12, school: {id:2, name:"India"}},
    {name: "johnny", age: 56, school: {id:3, name:"USA"}}
];
let schools = data.reduce((acc, x) => {
  // Check if the school already exists
  let school = acc.find(y => y.id === x.school.id);
  if (!school) {
    // If not, the current school is the school of the current person
    school = x.school;
    school.data = [];
    acc.push(school);
  } else {
    // Prevent duplication of school objects with the same id
    x.school = school;
  }
  school.data.push(x);
  return acc;
}, []);
console.log(schools);

＆＃13;

Answer 4

您可以将lodash库与groupBy一起使用

let x = [
    {name: "james", age: 10, school: {id:1, name:"London"}},
    {name: "james_2", age: 11, school: {id:1, name:"London"}},
    {name: "john", age: 12, school: {id:2, name:"India"}},
    {name: "johnny", age: 56, school: {id:3, name:"USA"}}
]


var result2 = _.chain(x)
    .groupBy(function(o){return o.school.name})
    .pairs()
    .map(function (currentItem) {
        return _.object(_.zip(["school", "name"], currentItem));
    })
    .value();
console.log(result2);

检查这个jsFiddle： - http://jsfiddle.net/6yasy30a/

Answer 5

let x = [
    {name: "james", age: 10, school: {id:1, name:"London"}},
    {name: "james_2", age: 11, school: {id:1, name:"London"}},
    {name: "john", age: 12, school: {id:2, name:"India"}},
    {name: "johnny", age: 56, school: {id:3, name:"USA"}}
];

let result = [];
for(var i = 0; i < x.length; i++) {
  var person = x[i];
  var school = result.find(s => s.id === person.school.id);
  if(!school) {
    school = {
      id: person.school.id,
      name: person.school.name,
      data: []
    };
    result.push(school);
  }
  school.data.push(person);
}

console.log(result);

Answer 6

如果id不存在，使用reduce并简单地将新对象推送到结果数组中，否则只需更新找到的对象中的数据数组

const myArray = x.reduce((res, data) => {
  const found = res.find(o => o.id === data.school.id);

  if (!found) {
    res.push({
        id: data.school.id,
        name: data.school.name,
        data: [data]
    });
  } else {
    found.data.push(data);
  }
  return res;
}, []);


console.log(myArray)

将属性对象拉为父对象

6 个答案: