Is there any kind of wildcard operator in the Durandal observable plugin, to subscribe to a change in any property? - durandal

Question

Is there any kind of wildcard operator in the Durandal observable plugin, as there is in (for example) JsObservable?
The Durandal observable documentation gives this example:
var observable = require('plugins/observable');
var viewModel:{
firstName:'',
lastName:''
};
observable(viewModel, 'firstName').subscribe(function(value){
console.log('First name changed.');
});
viewModel.firstName = 'Test';
What I'd like to do is use a wildcard to subscribe to any changed property on the target. Something like this:
observable(viewModel, '*').subscribe(function(property, value){
console.log(property + ' changed.');
});
I don't see anything in the API documentation, but wondered if there was anything undocumented, or if anyone has a workaround to implement this behaviour.

Answer 1

Unfortunately, there is no wildcard operator for this functionality.
But you can easily create wrapper module for this functionality.
Here is small example:
var observable = require('plugins/observable');
var wildcardObservable = function(obj, changeCallback){
for(var prop in obj){
observable(obj, prop).subscribe(changeCallback);
}
}
var changeCallback = function() {
console.log('property changed.');
}
Usage:
var viewModel:{
firstName:'',
lastName:''
};
wildcardObservable(viewModel, changeCallback);

Answer 2

With thanks to U10 for the start above, (and with reference to a few examples on the web) I came up with the following, which uses a closure to track all the necessary properties. It's a bit messy but it does what I need for now - hopefully it will be of use to someone.
var ChangeTracker = (function () {
function ChangeTracker() {
}
ChangeTracker.prototype._trackChange = function (prop, target) {
var type = typeof (target[prop]);
var value = target[prop];
_logger.log("_trackChange", { target: target, prop: prop, type: type, value: value }, "CT");
_obs(target, prop).subscribe(function (newValue) {
var obj = {
target: target,
prop: prop,
newValue: newValue,
oldValue: value
};
_logger.log(">>>>>>>>>>>>>>> CHANGE!", obj, "CT");
value = newValue;
});
};
ChangeTracker.prototype.TrackChanges = function (target) {
var _this = this;
for (var prop in target) {
if (target.hasOwnProperty(prop)) {
this._trackChange(prop, target);
}
var underlying = ko.utils.unwrapObservable(target[prop]);
if (underlying instanceof Array) {
ko.utils.arrayForEach(underlying, function (item) {
_this.TrackChanges(item);
});
} else if (typeof underlying === "object") {
this.TrackChanges(underlying);
}
}
}
};
return ChangeTracker;
})();