ng-repeat filter on json object - angularjs

Question

I have a complex JSON structure as below:
My JSON object is like -
$scope.data = {
"Test 1": [
{
"paperName": "Physics Test",
"lkExamTypePk": 1,
"paperPK": "20",
"lkExamType": 2
}
],
"Test 2": [
{
"paperName": "Maths Test",
"lkExamTypePk": 2,
"paperPK": "23",
"lkExamType": 3
}
]
}
I am using this json to display in my html page and want to search key which is Test 1, Test 2, etc:
<input ng-model="filter.key" />
<table>
<tr ng-repeat="(key,val) in controllerName.data | filter:filter.key">
<td>
{{key}}
</td>
</tr>
</table>
But the problem is that filter works on array and on the values of JSON and I am getting error of not an array.
Error which I'm getting at the console
Error: [filter:notarray]

Answer 1

I think you problem is in how you refer your variabile. As I can see you are declaring your data array into $scope variabile with
$scope.data = { ... }
Then you try to access it referring to your controller with
controllerName.data
You can follow 2 different approaches, but you can't mix them.
1) $scope variabile
If you want to work into $scope, in your controller you must declare your variabile as follow:
$scope.data = { ... }
then into html you must refer to it like this (without controllerName):
<tr ng-repeat="(key,val) in data | filter:filter.key">
2) controller scope
If you want to work into controller's scope, in your controller you must declare your variabile as follow:
this.data = { ... }
then into html you can refer to it like this:
<tr ng-repeat="(key,val) in controllerName.data | filter:filter.key">
Hint
Generally a good practice, when you receive an error referring to a variable, is to print your variable's data into html to check that you are referring well to it, something like:
<pre>{{ data | json }}</pre>
Try with array instead of object
You can try using an array intead of a json object, as suggested by the error, something like this:
$scope.data = [
"Test 1": [{
"paperName": "Physics Test",
"lkExamTypePk": 1,
"paperPK": "20",
"lkExamType": 2
}],
"Test 2": [{
"paperName": "Maths Test",
"lkExamTypePk": 2,
"paperPK": "23",
"lkExamType": 3
}]
]