Selective history.back() using Backbone.js - 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();

Answer 2

I used the same answer from jevakallio, but I had the same problem that commenter Jay Kumar had: The routesHit doesn't subtract so hitting appRouter.back() enough times will take the user out of the app, so I added 3 lines:
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
this.routesHit = this.routesHit - 2; //Added line: read below
window.history.back();
} else {
//otherwise go to the home page. Use replaceState if available so
//the navigation doesn't create an extra history entry
if(Backbone.history.getFragment() != 'app/') //Added line: read below
this.routesHit = 0; //Added line: read below
this.navigate('app/', {trigger:true, replace:true});
}
}
});
And use the router method to navigate back:
appRouter.back();
Added lines:
1st one: Subtract 2 from routesHit, then when its redirected to the "back" page it'll gain 1 so it's actually like you did just a minus 1.
2nd one: if user is already at "home", there wont be a redirect so don't do anything to routesHit.
3rd one: If user is where he started and is being sent back to "home", set routesHit = 0, then when redirected to "home" routesHit will be 1 again.