Group an array of objects in AngularJS

Question

Based on an array looking like this:

var members = [
  {name: "john", team: 1},
  {name: "kevin", team: 1},
  {name: "rob", team: 2},
  {name: "matt", team: 2},
  {name: "clint", team: 3},
  {name: "will", team: 3}
];

I need to create an unordered list for each team.

Can it be done directly with ngRepeat and a filter maybe?

Or is it easier to reorganize the array into an array of teams with a list of members?

var teams = [
  {id: 1, members: ["john", "kevin"]},
  {id: 2, members: ["rob", "matt"]},
  {id: 3, members: ["clint", "will"]}
]

The nested ngRepeat would be easy to implement, but how do I go from the first array to this one in a simple / clever manner?

Note: The array doesn't come from the database but from an html table. So it's just a flat list of members.

 function MyController() { this.members = [ {name: "john", team: 1}, {name: "kevin", team: 1}, {name: "rob", team: 2}, {name: "matt", team: 2}, {name: "clint", team: 3}, {name: "will", team: 3} ]; } angular.module('app', []); angular.module('app') .controller('MyController', MyController); 

 <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.3/angular.min.js"></script> <div ng-app="app"> <div ng-controller="MyController as ctrl"> <ul> <li ng-repeat="member in ctrl.members">{{ member.name }} - {{ member.team }}</li> </ul> </div> </div> 

Answer 1

You have to group items. For this, I used reduce method in order to create a hash collection which looks like this:

{
  "1": [
    "john",
    "kevin"
  ],
  "2": [
    "rob",
    "matt"
  ],
   "3": [
     "clint",
      "will"
   ]
}

The reduce() method applies a function against an accumulator and each element in the array (from left to right) to reduce it to a single value.

The following step is to map this collection in an array . For this, you should use map method.

The map() method creates a new array with the results of calling a provided function on every element in this array.

 var members = [ {name: "john", team: 1}, {name: "kevin", team: 1}, {name: "rob", team: 2}, {name: "matt", team: 2}, {name: "clint", team: 3}, {name: "will", team: 3} ]; var groups = members.reduce(function(obj,item){ obj[item.team] = obj[item.team] || []; obj[item.team].push(item.name); return obj; }, {}); var myArray = Object.keys(groups).map(function(key){ return {team: key, name: groups[key]}; }); console.log(myArray); 

Answer 2

Expanding over the @Alexandru-Ionut Mihai's answer, (just to experience how powerful a reduce function is).. here's a single reduce without having to map it again to achieve the same thing. :)

 var members = [ {name: "john", team: 1}, {name: "kevin", team: 1}, {name: "rob", team: 2}, {name: "matt", team: 2}, {name: "clint", team: 3}, {name: "will", team: 3} ]; /*var teams = [ {id: 1, members: ["john", "kevin"]}, {id: 2, members: ["rob", "matt"]}, {id: 3, members: ["clint", "will"]} ]*/ var group_to_values = members.reduce(function(arr, item){ arr[item.team - 1] = arr[item.team - 1] || { id: item.team, members: []}; arr[item.team - 1].members.push(item.name); return arr; }, []); console.log(group_to_values); 

Answer 3

If you are using underscore.js, then you can use _.groupBy() method to group array of records on the basis of team.

function MyController() {
  this.members = [
    {name: "john", team: 1},
    {name: "kevin", team: 1},
    {name: "rob", team: 2},
    {name: "matt", team: 2},
    {name: "clint", team: 3},
    {name: "will", team: 3}
  ];

var grouped = _.groupBy(this.members, function(member) {
  return member.team;
});
}

Answer 4

You can use a groupBy filter like this

<ul ng-repeat="(key, value) in members | orderBy: 'team' | groupBy:ourGrouper">
      <li>{{key}}
        <ul>
          <li ng-repeat="mem in value | orderBy: 'name'">
            {{mem.name}}
          </li>
        </ul>
      </li>
    </ul>

See this FIDDLE

Answer 5

 var members = [ {name: "john", team: 1}, {name: "kevin", team: 1}, {name: "rob", team: 2}, {name: "matt", team: 2}, {name: "clint", team: 3}, {name: "will", team: 3} ]; var groups = members.reduce(function(obj,item){ obj[item.team] = obj[item.team] || []; obj[item.team].push(item.name); return obj; }, {}); var myArray = Object.keys(groups).map(function(key){ return {team: key, name: groups[key]}; }); console.log(myArray);