KnockoutJS binding when source is null/undefined

Answer 1

Most of these solutions do not work in a certain case for me, where I am setting an attribute:

  ...

The template and with bindings would not work here, because if I did not have an active descendant, then my div would be empty. For my solution, I created an observable method:

ko.observable.fn.get = function (propertyName, defaultValue) {
    var
    self = this(),
    propertyValue;

    if (self != null) {
        propertyValue = ko.unwrap(self[propertyName]);
    }

    return propertyValue || defaultValue;
}

Which allows me to change my binding to this:

  ...