Best practice for angular service return value?

Question

I have a number of angular services (e.g. a user service) which make various HTTP calls and I'm wondering what the best practice would be for handling errors. For example, I could do: function getAll(success, error) { $http.get('/api/users').then(success, error); } Or I could do: function getAll(success) { $http.get('/api/users').then(success, function(err) { success([]); }); }The advantage of the former is it is more configurable in case I wanted to do something special. However, the advantage of the second is that it keeps the controllers simpler and in the (hopefully rare) case that the server is down it won't simply throw an error but will just display blank/empty data.Is there any guideline or accepted best practice for this kind of situation?

Answer 1

I guess what you want to consider is where you want to react on an error.

In your later example,

function getAll(success) {

$http.get('/api/users').then(success, function(err) { success([]); });

}

you have no way of knowing whether the output is valid or not, while with your first example

function getAll(success, error) {

$http.get('/api/users').then(success, error);

}

you handle the error in a more controlled way.

However, my question is why you place your callback function into the service at all. You are creating bottlenecks with asynchronicity that aren't providing any advantage.

I assume the following scenarios:

1. The need for custom reactions on an error in a controller will eventually arise.
2. Bindings to the scope will be dependent on the outcome of a service call

So writing your services like this:

function getAll() {

return $http.get('/api/users');

}

and using them in your controllers like this:

userService.getAll().then(...)

is likely the easiest and cleanest solution.