Angular ng-repeat Error "Duplicates in a repeater are not allowed."

The solution is actually described here: http://www.anujgakhar.com/2013/06/15/duplicates-in-a-repeater-are-not-allowed-in-angularjs/

AngularJS does not allow duplicates in a ng-repeat directive. This means if you are trying to do the following, you will get an error.

// This code throws the error "Duplicates in a repeater are not allowed.
// Repeater: row in [1,1,1] key: number:1"
<div ng-repeat="row in [1,1,1]">

However, changing the above code slightly to define an index to determine uniqueness as below will get it working again.

// This will work
<div ng-repeat="row in [1,1,1] track by $index">

Official docs are here: https://docs.angularjs.org/error/ngRepeat/dupes

For those who expect JSON and still getting the same error, make sure that you parse your data:

$scope.customers = JSON.parse(data)

I was having an issue in my project where I was using ng-repeat track by $index but the products were not getting reflecting when data comes from database. My code is as below:

<div ng-repeat="product in productList.productList track by $index">
  <product info="product"></product>
 </div>

In the above code, product is a separate directive to display the product.But i came to know that $index causes issue when we pass data out from the scope. So the data losses and DOM can not be updated.

I found the solution by using product.id as a key in ng-repeat like below:

<div ng-repeat="product in productList.productList track by product.id">
  <product info="product"></product>
 </div>

But the above code again fails and throws the below error when more than one product comes with same id:

angular.js:11706 Error: [ngRepeat:dupes] Duplicates in a repeater are not allowed. Use 'track by' expression to specify unique keys. Repeater

So finally i solved the problem by making dynamic unique key of ng-repeat like below:

<div ng-repeat="product in productList.productList track by (product.id + $index)">
  <product info="product"></product>
 </div>

This solved my problem and hope this will help you in future.

What do you intend your "range" filter to do?

Here's a working sample of what I think you're trying to do: http://jsfiddle.net/evictor/hz4Ep/

HTML:

<div ng-app="manyminds" ng-controller="MainCtrl">
  <div class="idea item" ng-repeat="item in items" isoatom>    
    Item {{$index}}
    <div class="section comment clearfix" ng-repeat="comment in item.comments | range:1:2">
      Comment {{$index}}
      {{comment}}
    </div>
  </div>
</div>

JS:

angular.module('manyminds', [], function() {}).filter('range', function() {
    return function(input, min, max) {
        var range = [];
        min = parseInt(min); //Make string input int
        max = parseInt(max);
        for (var i=min; i<=max; i++)
            input[i] && range.push(input[i]);
        return range;
    };
});

function MainCtrl($scope)
{
    $scope.items = [
        {
            comments: [
                'comment 0 in item 0',
                'comment 1 in item 0'
            ]
        },
        {
            comments: [
                'comment 0 in item 1',
                'comment 1 in item 1',
                'comment 2 in item 1',
                'comment 3 in item 1'
            ]
        }
    ];
}

If by chance this error happens when working with SharePoint 2010: Rename your .json file extensions and be sure to update your restService path. No additional "track by $index" was required.

Luckily I was forwarded this link to this rationale:

.json becomes an important file type in SP2010. SP2010 includes certains webservice endpoints. The location of these files is 14hive\isapi folder. The extension of these files are .json. That is the reason it gives such a error. "cares only that the contents of a json file is json - not its file extension"

Once the file extensions are changed, should be all set.

Just in case this happens to someone else, I'm documenting this here, I was getting this error because I mistakenly set the ng-model the same as the ng-repeat array:

 <select ng-model="list_views">
     <option ng-selected="{{view == config.list_view}}"
         ng-repeat="view in list_views"
         value="{{view}}">
         {{view}}
     </option>
 </select>

Instead of:

<select ng-model="config.list_view">
     <option ng-selected="{{view == config.list_view}}"
         ng-repeat="view in list_views"
         value="{{view}}">
         {{view}}
     </option>
 </select>

I checked the array and didn't have any duplicates, just double check your variables.

Duplicates in a repeater are not allowed. Use 'track by' expression to specify unique keys.

Repeater: {0}, Duplicate key: {1}, Duplicate value: {2}

Example

<!DOCTYPE html>
<html lang="en" xmlns="http://www.w3.org/1999/xhtml">
<head>
    <meta charset="utf-8" />
    <title></title>
    <script src="angular.js"></script>

</head>
<body>
    <div ng-app="myApp" ng-controller="personController">
        <table>
            <tr> <th>First Name</th> <th>Last Name</th> </tr>
            <tr ng-repeat="person in people track by $index">
                <td>{{person.firstName}}</td>
                <td>{{person.lastName}}</td>
                <td><input type="button" value="Select" ng-click="showDetails($index)" /></td>
            </tr>

        </table> <hr />
        <table>
            <tr ng-repeat="person1 in items track by $index">
                <td>{{person1.firstName}}</td>
                <td>{{person1.lastName}}</td>
            </tr>
        </table>
        <span>   {{sayHello()}}</span>
    </div>
    <script> var myApp = angular.module("myApp", []);
        myApp.controller("personController", ['$scope', function ($scope)
        { 
            $scope.people = [{ firstName: "F1", lastName: "L1" },
                { firstName: "F2", lastName: "L2" }, 
                { firstName: "F3", lastName: "L3" }, 
                { firstName: "F4", lastName: "L4" }, 
                { firstName: "F5", lastName: "L5" }]
            $scope.items = [];
            $scope.selectedPerson = $scope.people[0];
            $scope.showDetails = function (ind) 
            { 
                $scope.selectedPerson = $scope.people[ind];
                $scope.items.push($scope.selectedPerson);
            }
            $scope.sayHello = function ()
            {
                return $scope.items.firstName;
            }
        }]) </script>
</body>
</html>

If you call a ng-repeat within a < ul> tag, you may be able to allow duplicates. See this link for reference. See Todo2.html

Duplicates in a repeater are not allowed. Use 'track by' expression to specify unique keys. Repeater: sdetail in mydt, Duplicate key: string: , Duplicate value:

I faced this error because i had written wrong database name in my php api part......

So this error may also occurs when you are fetching the data from database base, whose name is written incorrect by you.

My JSON response was like this:

{
    "items":  [
        {
            "index": 1, "name": "Samantha", "rarity": "Scarborough","email": "maureen@sykes.mk"
        },{ 
            "index": 2, "name": "Amanda", "rarity": "Vick", "email": "jessica@livingston.mv"
        }
    ]
}

So, I used ng-repeat = "item in variables.items" to display it.