在数组字段上展平嵌套的对象数组 [英] Flatten a nested array of objects over a array field

问题描述

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'}]]

所需的输出：

[{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'}]

请提出建议！我试图用lodash / underscore完成这个。

Please suggest! I am trying to accomplish this using lodash/underscore.

推荐答案

将原始数组中的每个项目映射到一个新数组，根据 addr 字段的数量的项目数。使用concat将所有内容展平为一个新数组。

Map every item in the original array to a new array, with a number of items according to the number of addr fields. Using concat flatten everything to a new array.

您可以使用 Object.assign（） ，因为它不支持IE。但是，由于您使用的是角度，因此可以使用 angular.extend 代替。

You can create new items using 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 instead.

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);

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