web administration - Page 742

Backbone.js Model change events in nested collections not firing as expected

- by Pallavi Kaushik

I'm trying to use backbone.js in my first "real" application and I need some help debugging why certain model change events are not firing as I would expect. I have a web service at /employees/{username}/tasks which returns a JSON array of task objects, with each task object nesting a JSON array of subtask objects. For example, [{ "id":45002, "name":"Open Dining Room", "subtasks":[ {"id":1,"status":"YELLOW","name":"Clean all tables"}, {"id":2,"status":"RED","name":"Clean main floor"}, {"id":3,"status":"RED","name":"Stock condiments"}, {"id":4,"status":"YELLOW","name":"Check / replenish trays"} ] },{ "id":47003, "name":"Open Registers", "subtasks":[ {"id":1,"status":"YELLOW","name":"Turn on all terminals"}, {"id":2,"status":"YELLOW","name":"Balance out cash trays"}, {"id":3,"status":"YELLOW","name":"Check in promo codes"}, {"id":4,"status":"YELLOW","name":"Check register promo placards"} ] }] Another web service allows me to change the status of a specific subtask in a specific task, and looks like this: /tasks/45002/subtasks/1/status/red [aside - I intend to change this to a HTTP Post-based service, but the current implementation is easier for debugging] I have the following classes in my JS app: Subtask Model and Subtask Collection var Subtask = Backbone.Model.extend({}); var SubtaskCollection = Backbone.Collection.extend({ model: Subtask }); Task Model with a nested instance of a Subtask Collection var Task = Backbone.Model.extend({ initialize: function() { // each Task has a reference to a collection of Subtasks this.subtasks = new SubtaskCollection(this.get("subtasks")); // status of each Task is based on the status of its Subtasks this.update_status(); }, ... }); var TaskCollection = Backbone.Collection.extend({ model: Task }); Task View to renders the item and listen for change events to the model var TaskView = Backbone.View.extend({ tagName: "li", template: $("#TaskTemplate").template(), initialize: function() { _.bindAll(this, "on_change", "render"); this.model.bind("change", this.on_change); }, ... on_change: function(e) { alert("task model changed!"); } }); When the app launches, I instantiate a TaskCollection (using the data from the first web service listed above), bind a listener for change events to the TaskCollection, and set up a recurring setTimeout to fetch() the TaskCollection instance. ... TASKS = new TaskCollection(); TASKS.url = ".../employees/" + username + "/tasks" TASKS.fetch({ success: function() { APP.renderViews(); } }); TASKS.bind("change", function() { alert("collection changed!"); APP.renderViews(); }); // Poll every 5 seconds to keep the models up-to-date. setInterval(function() { TASKS.fetch(); }, 5000); ... Everything renders as expected the first time. But at this point, I would expect either (or both) a Collection change event or a Model change event to get fired if I change a subtask's status using my second web service, but this does not happen. Funnily, I did get change events to fire if I added one additional level of nesting, with the web service returning a single object that has the Tasks Collection embedded, for example: "employee":"pkaushik", "tasks":[{"id":45002,"subtasks":[{"id":1..... But this seems klugey... and I'm afraid I haven't architected my app right. I'll include more code if it helps, but this question is already rather verbose. Thoughts?

Search Results

Search found 44267 results on 1771 pages for 'web administration'.

Page 742/1771 | < Previous Page | 738 739 740 741 742 743 744 745 746 747 748 749 | Next Page >

- by Pallavi Kaushik

- by Chris Aldrich

- by Chas Emerick

- by Anoop

- by Itay Levin

- by keepsmilinyaar

- by mary

- by aelshereay

- by user1300580

- by user1700184

- by Steve Hiner

- by Phil

- by abcdd007

- by megala

- by GigaPr

- by GigaPr

- by chunkyb2002

- by tushar

- by Matt Lewis

- by Mark

- by Frido

- by Edgar Pérez

- by SilverLight

- by pilcrow

- by JP.

< Previous Page | 738 739 740 741 742 743 744 745 746 747 748 749 | Next Page >