knockout.hx is an extern file for Knockout.
haxelib install knockout.hx
// Create an observable
var observable:Observable<String> = Knockout.observable("hello");
// Writing
observable.set("good by");
// other way
observable << "good by";
// Reading
var value = observable.get();
// Implicit Casts
var value:String = observable;
//Activating
Knockout.applyBindings({prop:observable});
See example: text/Test.hx