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

I am defining a custom filter like so:

<div class="idea item" ng-repeat="item in items" isoatom>    
    <div class="section comment clearfix" ng-repeat="comment in item.comments | range:1:2">
        ....
    </div>
</div>

As you can see the ng-repeat where the filter is being used is nested within another ng-repeat

The filter is defined like this:

myapp.filter('range', function() {
    return function(input, min, max) {
        min = parseInt(min); //Make string input int
        max = parseInt(max);
        for (var i=min; i<max; i++)
            input.push(i);
        return input;
    };
});

I'm getting:

Error: Duplicates in a repeater are not allowed. Repeater: comment in item.comments | range:1:2 ngRepeatAction@https://ajax.googleapis.com/ajax/libs/angularjs/1.1.4/an

Solution 1:

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

Solution 2:

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

$scope.customers = JSON.parse(data)

Solution 3:

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.