Edit in JSFiddle

$(document).ready(function () {
    
        var gogInterface = new IGoogleMapsService('map-canvas');
        gogInterface.init();
        gogInterface.setZoom(15);

        gogInterface.getServicesByKeyword('bar','5000');
        gogInterface.getServicesByKeyword('drink', '5000');
        gogInterface.getServicesByKeyword('cafe','5000');
        gogInterface.getServicesByKeyword('empire', '5000');

        gogInterface.getServicesByTypes(['food', 'cafe', 'bar'], '5000');

    });



/*
*Contains all configuration used by GoogleApiClass
*/
var configurations = {
    geolocationFailed: "Error: Geolocation failed.",
    geolocationNotSupported: "Error: Geolocation isn\'t supported",
    locationFound: "You are here",
    defaultLocation: new google.maps.LatLng(44.493587, 11.346584) //Bologna
};



    /**
    *This class allows you to find informations about places and services around you
    *
    *Samuele Resca
    **/
function IGoogleMapsService(destinationDivId) {
    /**
    *The object that contains the map
    **/
    this.map = null;
    /**
    *ID of map destination div
    **/
    this.destinationDiv = destinationDivId;
    /**
    *Obj that contains all information about services
    **/
    this.service = null;
    /*
    *Obj that contains the information about infowindow
    */
    this.infowindow = null;
    /*
    *Contains all configuration information
    */
    this.config = configurations;
    /*
    *Array of  new google.maps.Marker() Objects
    */
    this.markerList = new Array();
    /*
    *Used in asynchronous action 
    */
    self = this;


    /*
    *Initialize the map 
    */
    this.init = function () {
        //default zoom
        var mapOptions = {
            zoom: 6
        };
        //Init the map
        map = new google.maps.Map(document.getElementById(this.destinationDiv),
            mapOptions);
        if (navigator.geolocation) {
            //HTML 5 geolocation
            this.getPositionHTML5();
        } else {
            //NO HTML 5 geolocation
            noGeolocation(false);
        }
    }
    /**
    *Handles browsers that not support geolocation
    **/
    this.noGeolocation = function (errorFlag) {
        if (errorFlag) {
            var content = this.config.geolocationNotSupported;
        } else {
            var content = this.config.geolocationFailed;
        }

        var options = {
            map: map,
            position: self.config.defaultLocation,
            content: content
        };

        this.infowindow = new google.maps.InfoWindow(options);
        map.setCenter(options.position);
    }
    /**
    *Get the current position and creates new info window
    **/
    this.getPositionHTML5 = function () {
        navigator.geolocation.getCurrentPosition(function (position) {
            var pos = new google.maps.LatLng(position.coords.latitude,
                                             position.coords.longitude);

            //Set the default position
            //var pos = self.config.defaultLocation

            this.infowindow = new google.maps.InfoWindow({
                map: map,
                position: pos,
                content: self.config.locationFound
            });

            map.setCenter(pos);

        }, function () {
            noGeolocation(true);
        });
    };
    /**
    *Set the zoom level
    **/
    this.setZoom = function (zoomLevel) {
        map.setZoom(zoomLevel);
    };
    /*
    *Add new google.maps.Marker in the markerList
    */
    this.addMarker = function (marker) {
        for (i = 0; i < self.markerList.length; i++) {
            if (self.markerList[i].position.lat() == marker.position.lat() &&
               self.markerList[i].position.lng() == marker.position.lng()) {
                return;
            }
        }
        self.markerList.push(marker);
    };
    /*
    *Creates a marker in a specific latlng position and add it in the markerList
    */
    this.createMarker = function (place) {
        var placeLoc = place.geometry.location;
        //new marker 
        var marker = new google.maps.Marker({
            map: map,
            position: place.geometry.location,
        });

        self.addMarker(marker);

        
        //Add listener on click
        google.maps.event.addListener(marker, 'click', function () {
            infowindow.setContent(place.name);
            infowindow.open(map, this);
        });
    }
    /*
     *Finds all information about a services using  keywords
     *@keywordValue: search places using a keywords
     *@radiusValue: https://developers.google.com/maps/documentation/javascript/places#place_search_requests
     */
    this.getServicesByKeyword = function (keywordValue, radiusValue) {

        navigator.geolocation.getCurrentPosition(function (position) {
            //get current position
            var pos = new google.maps.LatLng(position.coords.latitude,
                                             position.coords.longitude);
            //creates new request
            var request = {
                location: pos,
                radius:radiusValue,
                keyword: keywordValue
            };
            self.getServices(request)
        });
    }

    /*
     *Finds all information about a services using  types
     *@typesValue: search places using a types  : https://developers.google.com/places/supported_types
     *@radiusValue: https://developers.google.com/maps/documentation/javascript/places#place_search_requests
     */
    this.getServicesByTypes = function (typesValue, radiusValue) {

        navigator.geolocation.getCurrentPosition(function (position) {
            //get current position
            var pos = new google.maps.LatLng(position.coords.latitude,
                                             position.coords.longitude);
            //creates new request
            var request = {
                location: pos,
                radius: radiusValue,
                types: typesValue
            };
            self.getServices(request)
        });
    }

    /*
    *Return services
    */
    this.getServices = function (request) {
        //init the service object
        service = new google.maps.places.PlacesService(map);
        service.nearbySearch(request, callback);

        //Services callback:
        //set information using createMarker function
        function callback(results, status) {
            if (status == google.maps.places.PlacesServiceStatus.OK) {
                for (var i = 0; i < results.length; i++) {
                    var place = results[i];
                    self.createMarker(results[i]);
                }
            }
           // alert(self.markerList.length);

        }
    };
  
};

<div id="map-canvas" style="height:400px"></div>