filter.js

 function filterByResponse(poi, responseText) {
        var responseJson = JSON.parse(responseText);
        // As a response we get dictionary with reachable points.
        // In request we have set it up as id: coords, so keys of the dictionary are indices of the reachable points.
        var reachablePointsKeys = Object.keys(responseJson.sources.source1.points);
        
        var unreachablePoiKeys = Object.keys(poi).filter(function(elem) {
            return reachablePointsKeys.indexOf(elem) == -1;
         });

        var reachablePoints = reachablePointsKeys.map(function(i){
          return poi[i];
        });
        var unreachablePoints = unreachablePoiKeys.map(function (i) {
            return poi[i];
        });
     	  
        return {reachable: reachablePoints, unreachable: unreachablePoints };
      }