knockout mapping with computed fields

knockout-mapping-plugin, knockout.js

Solution

Here's a working copy of your fiddle, I had to make a lot of assumptions as your fiddle wasn't even correct javascript and seemed quite confused and didn't even reference knockout

var PaidPeople = function(data) {
    var self = this;
    ko.mapping.fromJS(data, {}, this);
    this.fullName = ko.computed(function () {
                    return self.Name() + " : just ";
                });
}

var PayinyVM = function (data) {
                var self = this;

                ko.mapping.fromJS(data, {
                    'model' : {
                        create: function(options) {
                            return new PaidPeople(options.data);
                    }                        
                  }
                }, self);                
            };

var data = {model:[{__type: "PaidPeople:#model", Amount:110, Attendee:1, Name:'John'}]};

ko.applyBindings(new PayinyVM(data)); ​

and a fiddle that works : http://jsfiddle.net/qeUHd/

Problem

I'm getting data from a WCF service,and i map, and bind the data with my DOM object : ``` var PayinyVM = {}; $.getJSON('/service/PaidService.svc/PaidList', function (data) { var tmp = JSON.stringify(data.d); PayinyVM.model = ko.mapping.fromJSON(tmp); ko.applyBindings(PayinyVM); }); ``` the result is shown as excepted on my DOM bind it to model. What I couldn't find out is how to add some computed observable let's say my data is returning people with FirstName and LastName, how can I make a computed observable FullName with FN + ' ' + LN.

Original source