How to get ID of layer in feature group on click

Question

I have a feature group containing several markers.

And I have this code to respond to a click on any of the markers:

        sampleFeatureGroup.on("click", function(){ 
            alert(this.id);  // something like this
        });

I want to be able to get the id of the marker which is clicked on from within the function, however "this" refers to the feature group, so I cannot find the id of the marker clicked on, this seems like it should be easy but I can't figure it out.

Answer 1

You must use eachLayer to iterate through the featureGroup, and then bind a function to the click event, like this:

group.eachLayer(function(layer) {
  layer.on('click', function(){
    alert(this._leaflet_id)
  });
});

Here's a working example on Plunker: http://plnkr.co/edit/4fh7vhVet8N0iD4GE3aN

And here's the reference to eachLayer: http://leafletjs.com/reference.html#layergroup-eachlayer

Answer 2

Although it is possible to retrieve the ID using this._leaflet_id, this is not best practice because variables prefixed with _ should be treated as private.

Instead, it would be better to use the getLayerId() function like below:

group.eachLayer(function(layer) {
  layer.on('click', function(){
    alert(group.getLayerId(layer))
  });
});