Register single dependency

[ceilfors]

Is your feature request related to a problem? Please describe.
When I need to register a single dependency, the current Laconia API is asking me to return an object, which lead to a verbose code.

const instances = ({ env }) => ({
  orderStream: new KinesisOrderStream(env.ORDER_STREAM_NAME)
});

exports.handler = laconia(kinesis(app))
  .register(instances);

Describe the solution you'd like

exports.handler = laconia(kinesis(app))
  .register("orderStream", ({env}) => new KinesisOrderStream(env.ORDER_STREAM_NAME) );

This will also allow users to decouple their factories better from Laconia:

exports.handler = laconia(kinesis(app))
  .register("orderStream", ({env}) => myOwnFactory(env.ORDER_STREAM_NAME) );

[hugosenari]

Suggestion, add helper to convert to expected type:

const simple = (obj = {}) => deps => Object
    .entries(obj)
    .reduce((result, [key, fn]) => ({ ...result, [key]: fn(deps) }), {});

const constants = (obj = {}) => () => Object
    .entries(obj)
    .reduce((result, [key, value]) => ({ ...result, [key]: value }), {});

usage:

laconia(app)
    .register(simple({
        orderStream: ({env}) =>  myOwnFactory(env.ORDER_STREAM_NAME)
    }))
    .register(constants({
        ONE: 1,
        foo: 'bar'
    })); 

[ceilfors]

That's an interesting pattern! I guess if I want to register a single dependency, we can do it like this?

laconia(app)
    .register(single("orderStream", ({env}) =>  myOwnFactory(env.ORDER_STREAM_NAME)))

What are the pro and cons between the two approaches?

[hugosenari]

	Adapter Pattern	Method Overload
Add feature without change core code	OK	NOK
Easier to test	OK	NOK
Less verbose	NOK	OK
Less imports	NOK	OK

[ceilfors]

Thanks @hugosenari! It looks like the pro and cons can be derived into:

	Adapter Pattern	Method Overload
Framework maintainability	OK	NOK
User experience	NOK	OK

From the framework point of view, I think we should prefer user experience. On the other hand, I don't think they're mutually exclusive, if there are enough common adapter patterns in the user land, we should try to absorb it into the framework.

That said, would you be interested to make a PR for this feature?

[hugosenari]

The pull request that add .set(name, factory, options) as alias for .register(factory, options);

I'm not sure about naming, but is better than my other approach that tried to overload register. ;-)

[ceilfors]

@hugosenari I didn't realize how difficult it is to overload things in JavaScript, my bad. Maybe adding a new method is a good way to go, I'll continue the conversation in the PR.