javascript - AngularJS, is this way of using service good?

Question

i've this HTML:

<p>Hello {{name}}</p>

and the controller is:

function myCtrl(scope, service) {
    scope.name = service.getUsername(); // service.getUsername() return "World!"
}
myCtrl.$inject = ['$scope', 'originalService'];

The service works fine, so i don't paste the code here... In this case the result is "Hello world!" I changed the HTML in this way:

<p>Hello {{service.getUsername()}}</p>

But this does not work.

I changed the controller:

function myCtrl(scope, service) {
    scope.ser = service;
}
myCtrl.$inject = ['$scope', 'originalService'];

and then the HTML

<p>Hello {{ser.getUsername();}}</p>

This works!

So my question is:

Is this the only way to use the functions of a service directly in the HTML, or i'm missing something?

Answer 1

AngularJS templates can only invoke functions that are available on a scope. So, whatever approach you take you need to have your function on a scope.

If you want your service's functions to be directly invokable from a template you've got several options:

The one you've tried - that is, expose the whole service on a scope:

$scope.service = service;

and then in a template:

<p>Hello {{service.getUsername();}}</p>

This is one-liner in a controller and makes all the service methods available on a scope and thus to templates.

Expose methods one by one

to have precise control over what gets exposed:

$scope.getUsername = service.getUsername;

and then in a template:

<p>Hello {{getUsername();}}</p>

This requires more work exposing methods but gives you fine-grained control over what gets exposed.

Expose proxing methods:

$scope.getMyUsername = function() {
   //pre/post processing if needed 
   return service.getUsername();
};

You can use any of those methods or mix and combine them but at the end of the day a function must end up on a scope (either directly or through another object exposed on a scope).