emberjs: transitionToRoute Error no method 'addArrayObserver - ember.js

Question

From the 'job' route I am trying to transition to 'careers' route using following code.
<script type="text/x-handlebars" data-template-name="job">
<button {{action 'backToCareers' this}}>Back</button>
</script>
The controller with following gives 'Uncaught TypeError: Object # has no method 'addArrayObserver' ' error.
CareerApp.JobController = Ember.ObjectController.extend({
backToCareers: function(){
this.transitionToRoute('careers');
}
});
If I change the code(see below) to provide model object the error changes to 'Uncaught More context objects were passed than there are dynamic segments for the route: careers '
CareerApp.JobController = Ember.ObjectController.extend({
backToCareers: function(){
var jobs = CareerApp.Job.findAll();
this.transitionToRoute('careers', jobs);
}
});
Following is the code of my Model and the router
CareerApp.Job = Ember.Model.extend({
refNo: '',
title: ''
});
CareerApp.Job.reopenClass({
findAll: function(){
return $.getJSON("http://site/jobs").then(
function(response){
var jobs = Ember.A();
response.forEach(function(child){
jobs.pushObject(CareerApp.Job.create(child));
});
return jobs;
}
);
}
});
Router code
CareerApp.Router.map(function(){
this.resource('careers', {path: '/'});
this.resource('job', {path: '/jobs/:job_id'});
});
CareerApp.CareersRoute = Ember.Route.extend({
model:function(){
return CareerApp.Job.findAll();
}
});
CareerApp.CareersController = Ember.ArrayController.extend({
gradJobCount: function () {
return this.filterProperty('isExp', false).get('length');
}.property('#each.isExp')
});

Answer 1

The model hook is expected to return an array but you return a jQuery promise object. findAll should return an empty array which is filled when the callback is executed.
findAll: function() {
var jobs = [];
$.getJSON("http://site/jobs").then(function(response){
response.forEach(function(child){
jobs.pushObject(CareerApp.Job.create(child));
});
});
return jobs;
}

Answer 2

As you pass jobs to CarreersController, this one needs to be an ArrayController, maybe you have to define it manually