Filter unique values from a JSON

Question

I am using angularjs for my page. I want to filter the values from the JSON object, So that no redundancy exists. But I didn't find any way to get the unique values from angular ng-repeat. Is there anyway to do that?

Ok, Here is some description about the question. I have a JSON in this format. This JSON I am getting from a service. So we cant expect how the repeated data occure.

result = [
        {
            _id: "500004",
            subject: "Complete the task",
            date: "25 Aug, 2013"
        },      
        {
            _id: "500004",
            subject: "Complete the task",
            date: "25 Aug, 2013"
        },      
        {
            _id: "500005",
            subject: "Attend to the event",
            date: "2 Jan, 2013"
        },      
        {
            _id: "500065",
            subject: "Some task deadline",
            date: "20 Sep, 2013"
        },      
        {
            _id: "500004",
            subject: "Complete the task",
            date: "25 Aug, 2013"
        }
]

I want the output JSON to be with no repeated elements, So that my output will be something like this

result = [
        {
            _id: "500004",
            subject: "Complete the task",
            date: "25 Aug, 2013"
        },      
        {
            _id: "500005",
            subject: "Attend to the event",
            date: "2 Jan, 2013"
        },      
        {
            _id: "500065",
            subject: "Some task deadline",
            date: "20 Sep, 2013"
        }
]

Answer 1

var data = [
    {
        _id: "500004",
        subject: "Complete the task",
        date: "25 Aug, 2013"
    },      
    {
        _id: "500004",
        subject: "Complete the task",
        date: "25 Aug, 2013"
    },      
    {
        _id: "500005",
        subject: "Attend to the event",
        date: "2 Jan, 2013"
    },      
    {
        _id: "500065",
        subject: "Some task deadline",
        date: "20 Sep, 2013"
    },      
    {
        _id: "500004",
        subject: "Complete the task",
        date: "25 Aug, 2013"
    }
]

var uniqueNames = [];
var uniqueObj = [];

for(i = 0; i< data.length; i++){    

    if(uniqueNames.indexOf(data[i]._id) === -1){
        uniqueObj.push(data[i])
        uniqueNames.push(data[i]._id);        
    }       

}

console.log('uniqueObj',uniqueObj)

http://jsfiddle.net/C97DJ/165/

Answer 2

You can use 'unique'(aliases: uniq) filter in angular.filter module (https://github.com/a8m/angular-filter)

usage: colection | uniq: 'property'
you can filter by nested properties to : colection | uniq: 'property.nested_property'

So you can do something like that..

function MainController ($scope) {
 $scope.orders = [
  { id:1, customer: { name: 'foo', id: 10 } },
  { id:2, customer: { name: 'bar', id: 20 } },
  { id:3, customer: { name: 'foo', id: 10 } },
  { id:4, customer: { name: 'bar', id: 20 } },
  { id:5, customer: { name: 'baz', id: 30 } },
 ];
}

HTML: We filters by customer id, i.e remove duplicate customers

<th>All customers list: </th>
<tr ng-repeat="order in orders | unique: 'customer.id'" >
   <td> {{ order.customer.name }} , {{ order.customer.id }} </td>
</tr>

result: All customers list:
foo 10
bar 20
baz 30

Answer 3

You can make use of Angular UI which has the unique filter defined.

The source can be found here.

Basically, you can then make use of the filter as follows:

<div ng-repeat="item in result | unique:'_id'">
    //Body here
</div>