Question

I have an issue with Knockout where I prototype a user object where the observable properties of my object seem to be overwritten by the last occurrence.

Therefore I cannot use the same object more than once otherwise it will be overwritten.

Although this is hard to explain, see my fiddle.

http://jsfiddle.net/RSEcj/1/

What am I doing wrong? (or is this a bug in Knockout?) How can I fix the problem.

Answer 1

Because observables are functions and not properties they are represented by a single instance on the object prototype, unlike properties which will be created on the object when they are set.

You could use functional inheritance to achieve what you want.

http://jsfiddle.net/ypWQN/1/

var User = function(firstName, lastName){
    var that = {};

    that.firstName = ko.observable(firstName);
    that.lastName = lastName;

    return that;
};


var Employee = function(firstName, lastName){
    var that = User();

    that.firstName(firstName);
    that.lastName = lastName; 

    return that;
};

Hope this helps.