services.md

Services

Ivy includes a great and easy way of manipulating your services, together with performing some tasks like dependency injection.

Binding

Registering a service is done by using bind method.
First parameter should be a namespace of a given service, which will be binded to it, while second is a closure which is suppose to return a new instance of service.

bind('Ivy/CoolService', function() {
  return new CoolService();
});

Singleton

You can also directly bind a singleton object, by using singleton method.

singleton('Ivy/SingletonService', function() {
  return new SingletonService();
});

Namespace

Javascript doesn't come with the namespaces, however, Ivy does, and they provide you a handy way of working with your classes and objects.
Global function namespace, requires 2 arguments, one is the desired namespace, while the second is the class binding.

class Model {
  great() {
    return "this is cool!";
  }
}

namespace('Ivy/Model', Model);

Alias

You can also alias your namespaces.

alias('Ivy/Alias', 'Ivy/Real/Namespace');

Note that this is available by editing the services config file, more about it comes later.

Use

So, until now, we were talking about binding a namespace to the closure, but how are we suppose to get the binded object?

let obj = use('Ivy/Model');

and thats pretty much it. However, make sure that you understand few things.
First, in case that we have used a bind or singleton function to bind a given namespace, obj will contain the instantiated object of a service.
Second, when namespace is registered with namespace function, it will return only a class, so you would still need to do the new part.
And third, if theres an alias for that namespace, you can use it as a parameter, so use('Ivy/Alias'); is just fine.

Injection

By combining use and bind / singleton functions, we are able to perform the dependency injection in the binded class.

bind('Ivy/CoolService', function() {
  return new CoolService(use('Ivy/Dependecy1'), use('Ivy/Dependency2'));
});

Services config file

config/services.js has a list of service files that are being loaded on application bootup, as well as the list of aliases that are being created.

/**
 * Load application providers.
 */
'providers': [
    ...
    modules_path() + '/ivyframework/src/Config/ServiceProvider',
    ...
 ],
 ...

In case that you have a service provider file which you would like to be loaded during the application startup, put his path in the list of providers.

/**
 * Create a desired aliases.
 */
'alias': {
    ...
    'Config': 'Ivy/Config'
    ...
}

Aliases are created by writing a simple key: value in the list. Key is an alias, while value is the real namespace.