access ng-repeat $index from a inner ng-repeat - angularjs

Question

Knowing that ng-repeat create a scope, how do I access the $index of a parent ng-repeat from a child ng-repeat?
Markup
<div ng-repeat="first in arr">
here there is the first level $index
<div ng-repeat="second in first.arr">
in here I need access to the first level $index
</div>
</div>

Answer 1

Whenever ng-repeat iterate to create a DOM, it also does create a DOM, with new scope which prototypically inherited from the current running scope.
As you wanted to access the ng-repeat $index of outer ng-repeat in inner ng-repeat, you could use $parent.$index to indicate parent ng-repeat
<div ng-repeat="first in arr">
here there is the first level $index
<div ng-repeat="second in first.arr">
in here I need access to the first level {{$parent.$index}}
</div>
</div>
Though the cleaner solution to solve this problem would be, use ng-init on outer ng-repeat and have outer index in scope variable, by which you can get rid of $parent keyword.
<div ng-repeat="first in arr" ng-init="parentIndex=$index">
here there is the first level $index
<div ng-repeat="second in first.arr">
in here I need access to the first level {{parentIndex}}
</div>
</div>

Answer 2

<div ng-repeat="first in [1,2,3]">
here there is the first level {{$index}}
<div ng-repeat="second in ['a', 'b', 'c']">
in here I need access to the first level {{$parent.$index}} / {{$index}}
</div>
Output:
here there is the first level 0
in here I need access to the first level 0 / 0
in here I need access to the first level 0 / 1
in here I need access to the first level 0 / 2
here there is the first level 1
in here I need access to the first level 1 / 0
in here I need access to the first level 1 / 1
in here I need access to the first level 1 / 2
here there is the first level 2
in here I need access to the first level 2 / 0
in here I need access to the first level 2 / 1
in here I need access to the first level 2 / 2