How to be case sensitive when searching?

Question

JavaScript

Hello.
The question is. How to be case sensitive when searching by title?
Let's say the title consists of 2 words: Case in Text. If you write in the search field Case in the text - does not find. If to specify the case - finds.
Any ideas? Thank you.

$ionicModal.fromTemplateUrl('templates/search.html', {
            scope: $scope,
            focusFirstInput: true
        }).then(function(modal) {
            $scope.modalSearch = modal;
        });
$scope.openSearch = function() {
            $scope.modalSearch.show();

 $scope.itemsFilter = function(item) {
            var f = true;
            if (f && $scope.filter.query.length) {
                f = (item.title.indexOf($scope.filter.query) !== -1) || (item.article.indexOf($scope.filter.query) !== -1);
            }