There are some differences between what the Node.js pgmodule will accept and those defined as the PostgreSQL libpq Connection Strings.
The former allows a socket scheme and a database
parameter. The latter requires postgresql and dbname to
be use respectively. It should be possible to form the connect string
as a valid libpq URI without any query parameters, which the
Node.js pg module will also work with, including connecting via a
socket. This allows both versions to run using the same application
configuration file.
E.g.
Connect via a socket, using the peer method:
uri: "postgresql://%2Fvar%2Frun%2Fpostgresql/trip"