React to Press Enter, the AngularJS way

index.html

<div>
    <input 
        type          = "text"
        placeholder   = "Something to say"
        ng-model      = "target_variable"
        ng-pattern    = 'pattern_variable'
        jb-on-enter   = "executeCommand()"
    >
</div>

jbOnEnter.js

/* Adapted from EpokK's to check if a value has been passed to the input field through a ngModel.
   This can work alone or if the input[type="text"] has a ngPattern filter.
   Also, taken out the ng prefix to avoid possible confussion with regular Angular directives now
   or in the future.
*/
app.directive('jbOnEnter', function () {
        return function (scope, element, attrs) {
            element.bind("keydown keypress", function (event) {
               var key = typeof event.which === "undefined" ? event.keyCode : event.which;
                if(key === 13) {
                    var content = scope.$eval(attrs.ngModel);
                    if (typeof content != 'undefined' && content) {
                        scope.$apply(function (){
                            scope.$eval(attrs.jbOnEnter);
                        });
                        event.preventDefault();
                    }
                }
            });
        };
});