Angular.js: passing reference to directive

When first using the linking function on a directive I expected attribute values to be available through the attrs argument.

Turns out when you want to pass a reference from the parent scope you need to use the scope attribute in the directive definition object.

<pre ng-app="app" ng-controller="TestCtrl">
    controller: <span ng-bind="user.username"></span>
    directive: <span my-user="user"></span>
</pre>

​

var app = angular.module('app', []);

app.controller('TestCtrl', function($scope) {
    $scope.user = { username: 'Ben' };
});

app.directive('myUser', function() {
    return {
        template:
            '<span ng-bind="user.username"></span>',
        scope: { user: '=myUser' },
        link: function(scope, element, attrs) {
            /*
             *  returns: 'user'
             *    attrs.myUser is just the string, you
             *    should use scope on the directive
             *    definition object
             */
            console.log(attrs.myUser);

            // returns: 'Ben'
            console.log(scope.user.username);
        }
    };
});