javascript - Backbone: abort previous router callback execution -

suppose have 2 links on page:

<a href="#a">link a</a> <a href="#b">link b</a> 

and use backbone router handle in-app page navigation.

on routing link '#a', have registered listenera , listenerb '#b' both listenera , listenerb heavy task in background.

now, let's user clicks 'link a' , gap of few milliseconds, clicks 'link b'.

so, happens when listenera done execution, listenerb starts executing due single ui thread.

is there way, can block/abort/preempt execution of listenera if listenerb requested?

it's expected user see response latest action. previous actions should not honored if 2 actions similar.

to understand how backbone handles routes lets review chunk of code backbone.history:

 if (this._haspushstate) {         backbone.$(window).on('popstate', this.checkurl);       } else if (this._wantshashchange && ('onhashchange' in window) && !oldie) {         backbone.$(window).on('hashchange', this.checkurl);       } else if (this._wantshashchange) {         this._checkurlinterval = setinterval(this.checkurl, this.interval);       } 

if using modern browser 2nd if black subscribe hashchange event , time navigate link link call checkurl manage call appropriate action.

so direct answer queastion no, can't.

but can use few workarounds depending doing in actions.

---

1st solution.

use settimeout() or similar _.debounce() function. select links need protected or single treathed , navigate needed url mnually:

$(document.body).on('click', 'a:not([reference-to-out])', function(e){    e.preventdefault();    if (app.linktimeoutid) {       cleartimout(app.linktimeoutid);    }      app.linktimeoutid = settimeout(function () {           app.linktimeoutid = null;                      app.router.navigate(e.currenttarget.pathname, {trigger: true});    }, 500)   }); 

2nd solution

if heavy tasks network related (fetching collection, doing requests remote), track them keeping in object , cancel them when backbone.router fires 'route' event. prevent lot of needless operations.

3rd solution

i thinking $.deferred objects, in case should wrap controller's actions , keep track of them.