Question

I’m trying to use the Knockout Concurrency plugin in my project, and I’m currently fiddling with the example code, but I’m not getting it to work:

https://github.com/AndersMalmgren/Knockout.Concurrency/wiki/Getting-started

ViewModel = function() {
    this.name = ko.observable("John").extend({ concurrency: true});    
    this.children = [{ name: ko.observable("Jane").extend({concurrency: true })}, { name: ko.observable("Bruce").extend({concurrency: true })}];

    this.getData = function() {
        //Simulate backend data
        var data = { name: "John Doe", children: [{ name: "Jane Doe"},{ name: "Bruce Wayne"}, { name: "New row"}]};

        new ko.concurrency.Runner().run(this, data);
    }
}

ko.applyBindings(new ViewModel());

http://jsfiddle.net/rCVk4/3/

Nothing happens and the newly added item is not tracked by the plugin, does anyone know why?

Answer 1

Thanks for trying out my Plugin, really fast too, I uploaded the code today!

The plugin does indeed support tracking of deleted and added rows. But for it to know which rows are what It needs you to supply it with a mapper

var mappings = {  
    children: {
        key: function(item) {
            return ko.utils.unwrapObservable(item.id);
        },
        create: function(data) {
            return { id: data.id, name: data.name };
        }                            
    }
};

The name children corresponds to the name of the array.

The Key method is used to identify the property used as an identifier.

The Create method is used to create new rows (Added rows).

You can download the MVC3 sample from Github for a fully featured Demo, also please try out this Fiddle

http://jsfiddle.net/7atZT/