code: function () { $assertEveryCalledOnce (function (method, before, after) {
  
          var compo = $singleton (Component, {
                          method: $bindable (function (x) { method ()
                              return 42 }) })
  
          compo.method.onBefore (function (_5) { before ()
              $assert (this === compo)
              $assert (_5, 5) })
  
          compo.method.onAfter (function (_5, _result) { after ()
              $assert (this === compo)
              $assert (_5, 5)
              $assert (_result, 42) })
  
          $assert (compo.method (5), 42) }) }
docs: /*  $overrideThis is a macro that requires a method to be overriden
   /*'overrideThis': function () {
  $assertThrows (function () { $singleton (Component, { foo: $overrideThis (function () {}) }) },
  _.matches ({ message: 'foo should be overriden' })) }, /*  $bindable lifts _.bindable to Component level, opening new venues to hooking onto existing impl,
  in ad-hoc way, with no need to specify hard-coded callback structure beforehand.
  
  Use to implement common beforeXXX and afterXXX semantics.