angular.js/docs/content/error/$injector/unpr.ngdoc

@ngdoc error
@name $injector:unpr
@fullName Unknown Provider
@description

This error results from the `$injector` being unable to resolve a required
dependency. To fix this, make sure the dependency is defined and spelled
correctly. For example:

```
angular.module('myApp', [])
  .controller('MyController', ['myService', function (myService) {
    // Do something with myService
  }]);
```

The above code will fail with `$injector:unpr` if `myService` is not defined. 

Making sure each dependency is defined will fix the problem, as noted below.

```
angular.module('myApp', [])
  .service('myService', function () { /* ... */ })
  .controller('MyController', ['myService', function (myService) {
    // Do something with myService
  }]);
```