EC

Effect Community•14mo ago

bastian

Implementing multiple services with shared and unique methods using Effect Typescript library

Hi there! I'm wrapping my head around how to find a good way to implement a multitude of services that all share a common interface but also provide additional properties / methods when being used directly. It's kinda like having

ServiceA

ServiceA

,

ServiceB

ServiceB

and

ServiceC

ServiceC

and all of them are able to say

hello()

hello()

but

ServiceB

ServiceB

also has an additional method

bark()

bark()

When I use those services in a certain part of my program, I just want to call

hello()

hello()

based on an id/tag that I want to use to pick the corresponding service from my context.

This is quite easy when using a shared interface for regular classes or when using

Context.Tag

Context.Tag

. But I can't get the former to work with

Effect.Service

Effect.Service

unless I specify the whole return type upfront and therefore lose any type inference, and the latter limits the implementation to exactly what's being defined by the Tag.

Do you have any suggestions for how to implement this properly? And ideally also an example how I can dynamically get a service from the current context based on the service class only? I tried several options but I'm not super happy with them and have the feeling that I just can't see the forest for the trees... thanks a lot!