mysql: NodeJS mysql module transforms localhost to 127.0.0.1 and fails connection

I am trying to connect to ProxySQL that is set-up to connect to a MySQL database. From command line, the following works. The port number 6033 is for ProxySQL.

mysql -u demo1 -P6033 --database=database -p

However, the connection to ProxySQL with this package does not work.

var connection = mysql.createConnection({
        "host" : "localhost",
        "port": 6033,
        "user": "demo1",
        "password" : "password",
        "database": "database"
    })
 connection.connect( (err) => { console.log(err.stack) } )

This is the error message.

Error: ER_ACCESS_DENIED_ERROR: ProxySQL Error: Access denied for user 'demo1'@'127.0.0.1' (using password: YES)

The user was created as

CREATE USER 'demo1'@'localhost' IDENTIFIED BY 'password';

I tried adding another user as 'demo'@'127.0.0.1' and granted privileges for the same; didn’t work.

How do I retain the definition above and get mysql to return a successful connection?