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JavaScript AngularJS An Introduction to Directives Directives: $observe

Fareez Ahmed
Fareez Ahmed
12,728 Points
Posted by Fareez Ahmed
Fareez Ahmed
12,728 Points

Stuck!

Hi, what's wrong with this code, could someone explain the logic behind it?

I wish the challenges here matched up the level of depth/examples in the videos. 

angular.module('myApp', [])
  .controller('myController', function ($scope) {
    $scope.title = 'My embedded title';
  })
  .directive('treehouseCourse', function () {
    return {
      link: function ($scope, $element, $attrs) {

        $attrs.$observe( courseTitle, function(){


        }){
          console.log( $scope.title );
        }

      }
    }
  });
index.html 
<!DOCTYPE html>
<html ng-app="myApp">
<head>
  <title>Angular.js</title>
  <script src="js/angular.js"></script>
  <script src="app.js"></script>
</head>
<body ng-controller="myController">

  <div treehouse-course course-title="{{title}}"></div>

</body>
</html>

2 Answers

Chris Shaw
Chris Shaw
26,676 Points
Chris Shaw
Chris Shaw
26,676 Points

Hi Fareez Ahmed,

You seem to have the general gist of what's required but some incorrect code within your observer, those errors are as follows:

  1. You're observing treehouseCourse which isn't a valid attribute for the treehouseCourse directive
  2. You're not logged the value of newValue to console.log
  3. You don't need your isInitialized code as the directive has already been initialized.

See the below.

$attrs.$observe('courseTitle', function(newValue, oldValue) {
  console.log(newValue);
});

One thing to remember is whenever an attribute is mentioned as course-title for example we need to remove the hyphen and camel case the attribute starting with the first letter of each additional word which in this case results in courseTitle.

Happy coding!

Chris Shaw
Chris Shaw
26,676 Points
Chris Shaw
Chris Shaw
26,676 Points

You're welcome.