Selective history.back() using Backbone.js

Question

I have a Backbone app. I'm using Backbone.history to enable use of the back button. We have a page (settings) that auto loads a popup requiring input from the user. If the user chooses cancel, I want to go back to the previous page. I can do this using window.history.back().

The problem is, if the user went directly to that page (app#settings) from another url (like google) by typing the url into the browser, I want to redirect the user to the home page (app/) rather than going back to google.

I haven't been able to figure out any way to do this. Backbone.history looks like it store information from the browser's back button, so it has a history even if they just arrived at the app. I also couldn't find a way to view the previous url.

Is this possible?

Answer 1

Wrap the back navigation logic in a method of your own. Perhaps on the router:

var AppRouter = Backbone.Router.extend({

  initialize: function() {
    this.routesHit = 0;
    //keep count of number of routes handled by your application
    Backbone.history.on('route', function() { this.routesHit++; }, this);
  },

  back: function() {
    if(this.routesHit > 1) {
      //more than one route hit -> user did not land to current page directly
      window.history.back();
    } else {
      //otherwise go to the home page. Use replaceState if available so
      //the navigation doesn't create an extra history entry
      this.navigate('app/', {trigger:true, replace:true});
    }
  }
});

And use the router method to navigate back:

appRouter.back();