0

In Angular JS we declare services and factories. We create a service by declaring a function. We do not call the function ourselves.

Does this mean that is declarative programming. I suppose, the framework does the imperative work?

What is the imperative work being done in the background?

user3490188
  • 499
  • 2
  • 6
  • 14

1 Answers1

1

Yes, Angular does most of the imperative work (in your terms) that is related to lifecycle of instances. Here are some things that Angular do for you:

  • Each service, factory and provider in Angular that is declared by developer, provides angular with constructor function of that service, instance created by factory or constructor function that returns object having $get() method that returns an instance of provider. More about this see here.
  • All services in Angular are singletons that are instantiated only once (when first time injected to some controller, service, directive or whatever). That means that it is possible to share state using same service injected to different controllers as example.
  • Besides of it for each service/factory Angular creates provider with the same name as service/factory appended with word "Provider" behind the scenes.

Controllers, directives and filters are very similar to services, but need some special treatment (because of scope/input to be injected). For them Angular also creates a lot of useful staff.

If to say the truth, for about half a year working with Angular every day and night, I noticed that stopped to use new at all, just because there is no need any longer - Angular cares about creating and destroying instances.

Community
  • 1
  • 1
Vadim
  • 8,701
  • 4
  • 43
  • 50