Prashant Ghimire Prashant Ghimire - 4 months ago 19
AngularJS Question

AngularJS services and promises best practice

I have an AngularJS application where I have

service
s that calls
$http
resource and returns a
promise
that I resolve in my controller. Here's a sample of what I'm doing:

app.service('Blog', function($http, $q) {
var deferred = $q.defer();
$http.get('http://blog.com/sampleblog')
.then(function(res) {
// data massaging stuffs
return deferred.resolve(res.data);
}, function(err) {
// may be some error message checking and beautifying error message
return deferred.reject(err);
});
// chain if further more HTTP calls
return deferred.promise;
});


But I could simply do the following as well:

app.service('Blog', function($http) {
return $http.get('http://blog.com/sampleblog');
});


And then do the validation, error beautifying, chaining promises, etc. at the
controller
level.

My question is : Which is considered as 'best practice', if any, in terms of code resiliency and flexibility? Or is there a better way to do it completely different than this ?

Answer

As per the concept behind MVC, controller should decide what to do with the promise.

The service should initiate the promise.

app.service('Blog', function($http) {
  return $http.get('http://blog.com/sampleblog');
});

And the controller should decide what to do when resolved.

$scope.response = Blog;

$scope.response.then(function(response) {
    DataProcessor.processData(response.data)
})
.error(function(error){
    ErrorHandler.handle(error);
})
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