Calling collection data on helper

Question

I'm trying to build a house rental website and implemented google maps markers for each listing. I have stored the lat,long of each house in the collection along with its title.

But I am not able to call {{olat}} on the helper side as I am able to on the view template to act as placeholder for each. How can I call collection data inside the helper give below.

Template.listing.rendered = function() {
    var tmpl = this;

    VazcoMaps.init({}, function() {

        tmpl.mapEngine = VazcoMaps.gMaps();

        tmpl.newMap2.addMarker({
            lat: 28.6508, //replace this with lat,long variable stored in collection
            lng: 77.3152, //for each listing
            zoom: 11
            icon: '/images/mark.png',
            draggable: false
        });

    });

};

Answer 1

So your olat value is available on your template's data context, and you want to retrieve it in your onRendered hook. Seems a good place to call Template.currentData():

Template.listing.onRendered(function () {
  var tmpl = this;
  var context = Template.currentData();

  VazcoMaps.init({}, function() {
    tmpl.mapEngine = VazcoMaps.gMaps();

    tmpl.newMap2.addMarker({
      lat: context.olat,
      lng: context.olong,
      zoom: 11,
      icon: '/images/mark.png',
      draggable: false
    });
  });
});