Custom marker with override.

marker.js

// Subclass marker
var CustomMarker = L.Marker.extend({
  // override the update function
  update: function(){
    //call the original update method
    L.Marker.prototype.update.call(this);
    
    // fire the update event
    this.fire("update");
    
    // return 'this' to make it chainable
    return this;
  }
});

// use like a regular marker
var myMarker = new CustomMarker([45.51, -122.67]);