javascript - Backbone router events - always two events per route? -

i using newer backbone event listening mechanism. in router initialize method, looks this:

     this.listento(this,'all',function(route,action){            console.log('router invoked,  route:',route,'action:',action);        }); 

in debugger, when put breakpoint on console.log statement, unsuspected.

for each new route, combination

route   action  route:x  null route     x 

so in real life looks like:

route        action   route:home   null route        home   route:index null route       index 

so question - why there 2 separate events being fired each route, , why differ above?

here proof:

because router.route fires 2 separate events per route operation:

route: function(route, name, callback) {   if (!_.isregexp(route)) route = this._routetoregexp(route);   if (_.isfunction(name)) {     callback = name;     name = '';   }   if (!callback) callback = this[name];   var router = this;   backbone.history.route(route, function(fragment) {     var args = router._extractparameters(route, fragment);     if (router.execute(callback, args, name) !== false) {       router.trigger.apply(router, ['route:' + name].concat(args));       router.trigger('route', name, args);       backbone.history.trigger('route', router, name, args);     }   });   return this; }, 

http://documentcloud.github.io/backbone/docs/backbone.html#section-152

the first 1 calls actual trigger router, ['route:' + name].concat(args) , second 1 first route event.