How can implement this https://jsonapi.org/ with Adonis.js?
Your question is too broad, no one could answer it unless if you hire a developer. Please be specific.
I use JSONAPI at my company but I use the VanillaSerializer to first serialize it to POJO, and then feed that into jsonapi-serializer library in my controllers. The upside of this method is you don’t have to write your own serializer, or wait for someone to release an AdonisJs compatible serializer but the downside is you’ll have a lot of boilerplate code for serialization and deserialization.
Or you can create your own JSONAPI serializer. This is a more scalable method but I don’t know of any JSONAPI serializer for AdonisJs at the time of this writing.