A reusable escape handler mixin that will call a function of your choice when escape is pressed and automatically detach when the scope is destroyed

escapeHandlerMixin.js

angular.module('myModule').factory('escapeHandler', function($document){
  var ESCAPE_KEY = 27;
  return function(scope, handler){
    var eventHandler = function(keyEvent){
      if(keyEvent.keyCode === ESCAPE_KEY){ // use `keyCode`, not `which`
        scope.$apply(handler);
      }
    };
    $document[0].addEventListener('keydown', eventHandler, true); // using capture mode
    
    scope.$on('$destroy', function(){
      $document[0].removeEventListener('keydown', eventHandler, true); // third argument must match the `addEventListener` call
    });
  };
});

someDirective.js

angular.module('myModule').directive('someDirective', function(escapeHandler){
  return {
    link: function(scope){
      scope.done = function(){
        //whatever your close logic is
      };
      escapeHandler(scope, scope.done);
      // or you can do an inline function
      escapeHandler(scope, function(){
        scope.hideTheDialog = true;
      });
    }
  }
});