ES6 按字段类型对数组对象进行分组

Question

是否有一种简洁的 es6 功能方法可以按类型对项目进行分组，因为它是不可变的？

accounts.json

   [
         {"account": {"name": "Bob's credit", "type": "credit", "id": "1"}},
         {"account": {"name": "savings", "type": "savings", "id": "2"}},
         {"account": {"name": "vacation savings", "type": "savings", "id": "3"}},
         {"account": {"name": "son's savings", "type": "savings", "id": "4"},
         {"account": {"name": "wife's credit card", "type": "savings", "id": "5"}
   ]

预计

[
{"savings": [
    {"account": {"name": "savings", "type": "savings", "id": "2"}},
    {"account": {"name": "vacation savings", "type": "savings", "id": "3"}},
    {"account": {"name": "son's savings", "type": "savings", "id": "4"}
]},

{"checking": [
   {"account": {"name": "wife's credit card", "type": "savings", "id": "5"}
]

Answer 1

您可以使用

Array#reduce

按其内部

type

属性的元素对列表进行分组：

const data = [
     {"account": {"name": "Bob's credit", "type": "credit", "id": "1"}},
     {"account": {"name": "savings", "type": "savings", "id": "2"}},
     {"account": {"name": "vacation savings", "type": "savings", "id": "3"}},
     {"account": {"name": "son's savings", "type": "savings", "id": "4"}},
     {"account": {"name": "wife's credit card", "type": "savings", "id": "5"}}
];

const res = data.reduce((acc, curr) => {
  if(!acc[curr.account.type]) acc[curr.account.type] = []; //If this type wasn't previously stored
  acc[curr.account.type].push(curr);
  return acc;
},{});

console.log(res);

Answer 2

现在可以使用最新发布的函数Object.groupBy(array,callbackFun):

const result = Object.groupBy(data, ({type}) => type);

代码更加简洁易读。