Angular filter for filtering objects and nested objects by one property

deep-filter.js

app
  .filter('deepFilter', function() {
    return function(items, value, prop) {
      if (!angular.isDefined(value) || value === '' || !angular.isDefined(prop) || prop === '') {
        return items;
      }

      return items.filter(function(item) {

        if (checkProp(item)) {
          return true;
        } else {
          return checkDeepProp(item)
        }

        function checkDeepProp(o) {
          var r = false;

          angular.forEach(o, function(value, key) {
            if (r) {
              return true;
            }
            if (angular.isArray(value)) {

              angular.forEach(value, function(nested) {
                if (r) {
                  return true;
                }
                if (checkProp(nested)) {
                  r = true;
                } else {
                  r = checkDeepProp(nested)
                }
              })

            } else {
              r = false;
            }
          });

          return r;
        }

        function checkProp(o) {
          if (o.hasOwnProperty(prop)) {
            propLower = o[prop].toLowerCase();
            valLower = value.toLowerCase();

            return propLower.indexOf(valLower) !== -1;

          } else {
            return false;
          }
        }

      });
    };
  })

demo.md

Codepen demo: http://codepen.io/Wlada/pen/xgYrPr