WISH: Get properties of a member object by member email

I wish I could use the API to look up members based on email such that I do not add them again and again and …

/members/email/{email}
Get properties of a member object by member email

Just like this API call below that I can use to find a member which is linked to a thirdparty, then I’d really like to be able to find a member just by supplying the email address.

/members/thirdparty/email/{email}
Get properties of a member object by linked thirdparty email 

It would be great if someone coded it, because I can not seem to find the file(s) that implement the /members/thirdparty/email/{email} API call