Check user's credentials with REST API

[RonSeal]

Apologies if this has already been answered or there is a plugin to do such a thing (my search terms dont seem to be finding me a solution).

I'm looking for a way with the REST API to check a user's credentials and if correct return the member object. I don't seem to see anything in the REST API documentation for this method.

Can anyone point me in the right direction?

Thanks in advance.