<div class='container'></div>

<script>
// Define models.  View is a div with a counter.
Tasks = Backbone.Collection.extend({localStorage: new Store("tasks")})
Tasks = new Tasks
Tasks.bind('add', function (task_model) {
  task_model.bind('change', function(){ render(this) })
  $('.container').append(render(task_model))
})

function render(model) {
  console.log('rendering, daily_times: ', model.get('daily_times'))
  var div = '<div class="current task_time" task_id="%id">%time</div>'
  var time_str = model.get('daily_times')['Jun 28 2011']
  div = div.replace('%id', model.id).replace('%time', time_str)
  $('div[task_id="%id"]'.replace('%id', model.id)).replaceWith(div)
  return div
}

// Start pinging
setInterval(ping, 1000)
Tasks.create({daily_times:{'Jun 28 2011':0}})
function ping() { 
  console.log('ping')
  Tasks.each(function(task) {
    var times = task.get('daily_times')
    times['Jun 28 2011'] += 1
    task.set({daily_times:times})
    console.log('incremented, time: ', task.get('daily_times')['Jun 28 2011'])
  })
}
</script>

Why doesn't the change event fire when I set daily_times in ping?

<div class='container'></div>

<script>
// Define models.  View is a div with a counter.
Tasks = Backbone.Collection.extend({localStorage: new Store("tasks")})
Tasks = new Tasks
Tasks.bind('add', function (task_model) {
  task_model.bind('change', function(){ render(this) })
  $('.container').append(render(task_model))
})

function render(model) {
  console.log('rendering, daily_times: ', model.get('daily_times'))
  var div = '<div class="current task_time" task_id="%id">%time</div>'
  var time_str = model.get('daily_times')['Jun 28 2011']
  div = div.replace('%id', model.id).replace('%time', time_str)
  $('div[task_id="%id"]'.replace('%id', model.id)).replaceWith(div)
  return div
}

// Start pinging
setInterval(ping, 1000)
Tasks.create({daily_times:{'Jun 28 2011':0}})
function ping() { 
  console.log('ping')
  Tasks.each(function(task) {
    var times = task.get('daily_times')
    times['Jun 28 2011'] += 1
    task.set({daily_times:times})
    console.log('incremented, time: ', task.get('daily_times')['Jun 28 2011'])
  })
}
</script>

Why doesn't the change event fire when I set daily_times in ping?

• javascript
• jquery
• backbone.js

Share Improve this question Follow edited Dec 9, 2011 at 8:27 Tomasz Nurkiewicz 341k7171 gold badges712712 silver badges679679 bronze badges asked Jun 28, 2011 at 20:59 Jesse AldridgeJesse Aldridge 8,1691010 gold badges5050 silver badges7878 bronze badges 1

• 2 Just a style ment, but you should name your Collection-extending Task object and your actual Task collection object differently. Reusing variables like that is bad for readability - I would call the first one TaskCollection and the second one tasks. – Jamie Penney Commented Jun 28, 2011 at 21:23

Add a ment  | 

1 Answer 1

Sorted by: Reset to default 5

It looks like var times is an object rather than a value. So when it uses the _.toEqual method to see if the new value is the same as the old value, its actually paring the object to itself and returns true, so backbone decides there is no need to fire the change event.

You can fire the change event explicitly with task.change().