在数组字段上展平嵌套的对象数组

Question

有一个对象a1 =

[{name:'x',age:21, addr:[{flat:1,add:'xyz'},{flat:2,add:'xsr'}]},
{name:'y',age:22, addr:[{flat:3,add:'xyz1'},{flat:4,add:'xsr1'}]]

期望的输出：

[{name:'x',age:21, addr:{flat:1,add:'xyz'}},
{name:'x',age:21, addr:{flat:2,add:'xsr'}},
{name:'y',age:22, addr:{flat:3,add:'xyz1'},
{name:'y',age:22, addr:{flat:4,add:'xsr1'}]

求推荐！我正在尝试使用 lodash/underscore.

来完成此操作

Answer 1

您可以迭代数组和内部数组来构建想要的结果。

var array = [{ name: 'x', age: 21, addr: [{ flat: 1, add: 'xyz' }, { flat: 2, add: 'xsr' }] }, { name: 'y', age: 22, addr: [{ flat: 3, add: 'xyz1' }, { flat: 4, add: 'xsr1' }] }],
    result = array.reduce(function (r, a) {
        return r.concat(a.addr.map(function (b) {
            return { name: a.name, age: a.age, addr: b };
        }));
    }, []);

console.log(result);

ES6

var array = [{ name: 'x', age: 21, addr: [{ flat: 1, add: 'xyz' }, { flat: 2, add: 'xsr' }] }, { name: 'y', age: 22, addr: [{ flat: 3, add: 'xyz1' }, { flat: 4, add: 'xsr1' }] }],
    result = array.reduce((r, a) => r.concat(a.addr.map(b => ({ name: a.name, age: a.age, addr: b }))), []);

console.log(result);

Answer 2

您可以使用 reduce()、forEach() 和 Object.assign() 来获得 return 想要的结果。

var data = [{name:'x',age:21, addr:[{flat:1,add:'xyz'},{flat:2,add:'xsr'}]},
{name:'y',age:22, addr:[{flat:3,add:'xyz1'},{flat:4,add:'xsr1'}]}];

var result = data.reduce(function(r, o) {
  o.addr.forEach(function(e) {
    r.push(Object.assign({name: o.name, age: o.age}, e));
  })
  return r;
}, []);

console.log(result)

Answer 3

将原数组中的每一项映射到一个新数组中，根据addr字段的个数来映射一个新的数组。使用 concat 将所有内容展平到一个新数组中。

您可以使用 Object.assign() if you're transpiling to ES5 with babel or similar, as it's not supported by IE. However, since you're using angular, you can use angular.extend 创建新项目。

ES5:

var arr = [
  {name:'x',age:21, addr:[{flat:1,add:'xyz'},{flat:2,add:'xsr'}]},
  {name:'y',age:22, addr:[{flat:3,add:'xyz1'},{flat:4,add:'xsr1'}]}
];
   
var result = [].concat.apply([], arr.map(function(item) {     
  return item.addr.map(function(addr) {
    return angular.extend({}, item, { addr: addr });
  });
}));

console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.5.8/angular.min.js"></script>

ES6:

const arr = [
  {name:'x',age:21, addr:[{flat:1,add:'xyz'},{flat:2,add:'xsr'}]},
  {name:'y',age:22, addr:[{flat:3,add:'xyz1'},{flat:4,add:'xsr1'}]}
];
   
const result = [].concat(...arr.map((item) => item.addr.map((addr) => Object.assign({}, item, { addr }))));

console.log(result);

在数组字段上展平嵌套的对象数组

Flatten a nested array of objects over a array field

javascript

underscore.js

angularjs

lodash