CODEWITHSUNDEEP
angularjsangularjs-scope
Whisher
Whisher

Reputation: 32716

angularjs using angular.extend to bind $scope to a service bad/good practice

I'd like to know if using 

angular.extend($scope,MyService);

Does it break oop encapsulation principle ?

Does it smell like MyService.call($scope) ?

Could you face variable and function conflicts ?

Upvotes: 0

Views: 376

Answers (1)

drew_w
drew_w

Reputation: 10430

Is this a bad/good practice?

Typically from my experience services are injected into the controller and then will be called from that scope. I wouldn't say that using extend to copy over functions and properties is necessarily bad, but it might mitigate some of the purposes of IoC (inversion of control), which is what injection in angular is based on.

Does it break oop...?

My understanding is that what you would get from this call is additional functions and service calls directly on your scope. This doesn't break OOP in the sense that scope is an object and would have functions applied. Provided those functions + properties make sense on the scope it seems like a fine thing to do from that perspective.

Does it smell like MyService.call($scope)?

As I said in the first paragraph - I don't see why you wouldn't just call the service and either share data or pass in references to objects to the service. Another pattern that is common in angular is to use a promise to process returned data in your scope. That looks like:

MyService.callFunction(parameters).then(function (data) {
  // process data here. Since this runs in $scope you can also use $scope normally.
  // $scope.$apply() is in progress and will complete when the function returns
});

All the service does is provide the data to the scope then. Point is that I think there are better patterns than "extend".

Can you face conflicts?

In the call angular.extend(a, b); data, properties and functions are copied from b to a. If something already exists on a it will be overwritten with the data from b. So technically the short answer is "yes", you can face conflicts.

The bottom line

So at the end of the day this isn't a bad pattern but there are probably more common patterns I would try to use first.

Upvotes: 2

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