Angular makes use of dependency injection everywhere. Dependency injection is when a function does not initialize the dependencies it needs. Instead, they are injected into the function as parameters. For example, when a module needs a route provider, it asks for one. The module does not care how or when the route provider was created; it just wants a reference.
You actually use the injector in everything you do in Angular. Angular just does it for you. We will look at $injector and understand how it works but, most likely, you will not need to use these functions.
We will quickly cover the common ways that objects are injected into functions in Angular. Using a controller as an example, we will cover the two most common methods. Both of these are using Angular's injection behind the scenes:
Defining the variables in a function: You just have to pass the name of the object you need injected. Here is an example that uses
$scopeand a service...