gistfile1.js

var sess;
 
ab.connect(
  // ...
  function (session) { // Connection callback
    // Authenticate
    var username = 'guest';
    var password = 'secret-password';

    // send authreq rpc call
    sess.authreq(username).then(
      function (challenge) {
        console.log("Received auth challenge", challenge);
        var signature = sess.authsign(password, challenge);

        // send auth rpc call
        sess.auth(signature).then(
          function(permissions) {
            console.log("Authentication complete", permissions);    
            // ... carry on with our connection setup, 
            // ... adding subscriptions, etc.
          },
          function() { console.log("Authentication failed"); });
      },
      function() { console.log("AuthRequest failed"); });
  },
  // ...
);