AngularJS: output array (with keys) from php in ng-repeat?

I have a rootScope variable that will contain category for products, and each category may or may not have children. This is how I assign the rootScope:

$rootScope.categoryList = $http.get('category').then((result) -> result.data) 

This will make request (to Laravel route) to get me arrays of category data, the design of the data looks something like this:

$data = array(
        {category: Category, children: array('child1, child2, child3')},
        {category: Category2, children: null},
        {category: Category3, children: array('anotherchild1, anotherchild2')}
    );

And the way i generate the array is this:

public static function GetCategoryListings($ignore=false) {
    $results = DB::table('category')->where('parent','-')->get();
    $data = array();

    if(!is_null($results)) {
        $i = 0;
        foreach($results as $result) {
            $data[$i]['category'] = $result;
            $child_result = DB::table('category')->where('parent',$result)->get();

            if(!is_null($child_result)) {
                foreach($child_result as $child) {
                    $data[$i]['children'][] = $child;
                }
            }
            else
                $data[$i]['children'] = null;

            $i++;
        }
    }
    return $data;
}

Now, I would like to print my output into the view in Angular, how will I do that? I did something like this:

<li ng-repeat="cat in categoryList">
                {{cat.category}}
            </li>

But it's not working, plus I couldn't output the children. Is there any way around this?

EDIT

Solved my problem by changing to something like this in my view:

<ul>
            <li ng-repeat="cat in categoryList">
                {{cat.category}}
                <ul ng-if="cat.children != null">
                    <li ng-repeat="ch in cat.children">{{ch}}</li>
                </ul>
            </li>
        </ul>