Dynamically adding properties to observable object

knockout.js

Solution

Since, `C` itself is not observable initially, the binding would not know that it needs to update when a change is made.

To make it update, you would either need to reset `Items` entirely:

this.loadData = function() {
    var existing = this.Items();
    existing.C = 3;
    this.Items(existing);
};

or call the `valueHasMutated` function of the observable, to force any subscribers to update like:

this.loadData = function() {
    this.Items().C = 3;
    this.Items.valueHasMutated();
};

Problem

I have a viewmodel like this, ``` function viewModel() { this.loadData = function() { this.Items().C = 3; }; this.Items = ko.observable({ A: 1}); this.Items().B = 2; } var vm = new viewModel(); ko.applyBindings(vm); vm.loadData(); ``` I am printing out the values like this, ``` <span data-bind="text: $root.Items().A"></span> <span data-bind="text: $root.Items().B"></span> <span data-bind="text: $root.Items().C"></span> ``` It prints out values of A and B, but not C? Thanks.

Original source