how to split array of objects into multiple array of objects by subvalue

Question

I need to split an Array by its objects subvalue (type). Let's assume I have following array:

[
  {id:1,name:"John",information: { type :"employee"}},
  {id:2,name:"Charles",information: { type :"employee"}},
  {id:3,name:"Emma",information: { type :"ceo"}},
  {id:4,name:"Jane",information: { type :"customer"}}
]

and I want to split the object by information.type so my final result looks like:

[
 {
  type:"employee",
  persons:
  [
   {id:1,name:"John",information: { ... }},
   {id:2,name:"Charles",information: { ... }
  ]
 },
{
  type:"ceo",
  persons:
  [
   {id:3,name:"Emma",information: { ... }}
  ]
 },
{
  type:"customer",
  persons:
  [
   {id:4,name:"Jane",information: { ... }}
  ]
 }, 
]

Underscore is available at my Project. Any other helper library could be included.

Of course I could loop through the array and implement my own logic, but i was looking for cleaner solution.

Answer 1

这恰好返回您想要的：

_.pairs(_.groupBy(originalArray, v => v.information.type)).map(p => ({type: p[0], persons: p[1]}))

Answer 2

You could use the groupBy function of underscore.js :

var empList = [
{id:1,name:"John",information: { type :"employee"}},
  {id:2,name:"Charles",information: { type :"employee"}},
  {id:3,name:"Emma",information: { type :"ceo"}},
  {id:4,name:"Jane",information: { type :"customer"}}
];
_.groupBy(empList, function(emp){ return emp.information.type; });

Answer 3

A solution in plain Javascript with a temporary object for the groups.

 var array = [{ id: 1, name: "John", information: { type: "employee" } }, { id: 2, name: "Charles", information: { type: "employee" } }, { id: 3, name: "Emma", information: { type: "ceo" } }, { id: 4, name: "Jane", information: { type: "customer" } }], result = []; array.forEach(function (a) { var type = a.information.type; if (!this[type]) { this[type] = { type: type, persons: [] }; result.push(this[type]); } this[type].persons.push({ id: a.id, name: a.name }); }, {}); document.write('<pre>' + JSON.stringify(result, 0, 4) + '</pre>');