delegate

delegate( selector, event, handler(ev,newVal,oldVal,from) ) listen for changes in a child attribute from the parent. The child attribute does not have to exist.

// create an observable
var observe = new can.Observe({
  foo : {
    bar : "Hello World"
  }
})

//listen to changes on a property
observe.delegate("foo.bar","change", function(ev, prop, how, newVal, oldVal){
  // foo.bar has been added, set, or removed
  this //-> 
});

// change the property
observe.attr('foo.bar',"Goodbye Cruel World")

Parameters

1. selector {String}

   The attributes you want to listen for changes in.

   Selector should be the property or property names of the element you are searching. Examples:

   "name" - listens to the "name" property changing
   "name, address" - listens to "name" or "address" changing
   "name address" - listens to "name" or "address" changing
   "address.*" - listens to property directly in address
   "address.**" - listens to any property change in address
   "foo=bar" - listens when foo is "bar"
   

2. event {String}

   The event name. One of ("set","add","remove","change")

3. handler {function(ev, newVal, oldVal, prop)}

   The callback handler called with:

   • newVal - the new value set on the observe
   • oldVal - the old value set on the observe
   • prop - the prop name that was changed

Returns