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JavaScript AngularJS Extending Inputs Extending Inputs: Optional require

Posted by eric francis
eric francis
5,705 Points

Why would a directive want to optionally require the NgModelController -- when it really is requiring the ngModel?

Q: Set the 'sometimesTwoWay' directive up to optionally require the NgModelController.

A: require: '?ngModel'

Why is the answer not 'require: "?ngModelController"' ?

app.js 
angular.module('treehouseCourse', [])
  .directive('sometimesTwoWay', function() {
    return {
      // YOUR CODE HERE
      require: '?ngModel'
    }
  });
index.html 
<!DOCTYPE html>
<html ng-app="treehouseCourse">
<head>
  <title>Angular.js</title>
  <script src="js/angular.js"></script>
  <script src="app.js"></script>
</head>
<body>

  <sometimes-two-way ng-model="course.description"></sometimes-two-way>

</body>
</html>

5 Answers

Bryan Knight
Bryan Knight
34,215 Points

The require property tells Angular that our directive requires the controller of another directive. In this case, we want to use the ngModel controller

Kristopher Van Sant
PLUS
Kristopher Van Sant
Courses Plus Student 18,830 Points
Kristopher Van Sant
Kristopher Van Sant
Courses Plus Student 18,830 Points

I'm not quite sure how to answer this so I hope someone can answer your question more clearly for you soon! But have you looked at angular's documentation for this yet? Hopefully it can help clear up the differences between ngModel and NgModelController.

https://docs.angularjs.org/api/ng/directive/ngModel

https://docs.angularjs.org/api/ng/type/ngModel.NgModelController

Kerry Rosado
Kerry Rosado
14,368 Points
Kerry Rosado
Kerry Rosado
14,368 Points

According to the angular documentation:

The ngModel directive binds an input,select, textarea (or custom form control) to a property on the scope using NgModelController, which is created and exposed by this directive.

Adam White
Adam White
10,571 Points
Adam White
Adam White
10,571 Points

Could someone please tell me the exact answer for this? I can't get my code to pass. Thanks.

Jazmine Stevenson
Jazmine Stevenson
2,303 Points

require: '?ngModel'

anduelpitushi
anduelpitushi
6,993 Points
anduelpitushi
anduelpitushi
6,993 Points

Just this :

require : '?ngModel'