Container.md

Container

Since it's a dependency injection container library (so many words), we need to start with our Container:

const DIC = require('dependencyinjection');

const myContainer = new DIC.Container(serviceLocator);

Registering services

To add a service to the container:

myContainer.register('serviceId', 'my/service');

The register method returns a Definition object. See ServiceDefinition for more info

Retrieving services

Now, this service can be retrieved anywhere using:

myContainer.get('serviceId');

Internally this will call the ServiceLocator.reslolve(serviceId) to retrieve the module Once retrieved, it will instantiate an instance and return it

By default all services are Singletons, once instantiated, the same object is allways returned @see ServiceDefinition::setSingleton()

Overwriting service parameters.

When working with non-singleton services. Some parameters are calculated at run-time. You thus need to be able to overwrite certain parameters when creating a service.

This can be done by passing in the parameters as the optional second argument to container.get();

Lets say you have the following service definition:

  {
    "myService": {
      "module": "ExampleService",
      "arguments": [
        "%foo"
      ],
      "singleton": false
    }
  }

you can now retrieve multiple instances of this service by doing the following calls:

container.get('myService', {
  foo: "some value"
});
container.get('myService', {
  foo: "some other value"
});

You can overwrite both services and parameters using this method.

Registering parameters

To add a parameter to the container:

myContainer.addParameter('parameterId', 'my-parameter');

Retrieving parameters

Now, this parameter can be retrieved anywhere using:

myContainer.getParameter('parameterId');

Container ServiceLocator

The container builder requires a ServiceLocator as an argument. A service locator is a duck that quacks like:

{
    /**
     * Resolve a serviceId and require the module
     *
     * @param serviceId
     * @returns {*} the resolved dependency
     */
    resolve: function resolve(serviceId) {}
}

RequireJs as a ServiceLocator

If you really like require, you can use the following:

const DIC = require('dependencyinjection');

var container = new DIC.Container({
    resolve: require
});

This package comes built in with a more advanced ServiceLocator that adds a lot of sugar. See ServiceLocator..

const DIC = require('dependencyinjection')

const myServiceLocator = new DIC.ServiceLocator();
const myContainer = new DIC.Container(myServiceLocator);