[keycloak-user] Javascript Adapter vs Node Adapter

Hi folks, I'm a junior javascript developer and am looking into ways to implement SSO using keycloak. My applications are javascript with backend rest node and front-end vue. Before I go deeper into implementation I wanted to understand why is there a javascript adapter and a node adapter as well. I understand that the javascript adapter is client side and the node adapter is server side. How do you authenticate a resource(end-point) from a client-side adapter? Another thing that's confusing me is keycloak.js, what is it? how is it used and its pros and cons? Thank you in anticipation and for bearing with the relatively noob questions. Regards, Adnan A. Khan