This can be set when initializing SlackStrategy or when calling authenticate. For example when initalizing SlackStrategy: 	passport.use(new SlackStrategy({ 	    clientID: '123-456-789’, 	    clientSecret: 'shhh-its-a-secret’ 	    callbackURL: 'https://www.example.net/auth/slack/callback', 	    scope: 'identify,read,post,client,admin’,             team: 'teamID’  	   }, function(accessToken, refreshToken, profile, done) { 	     User.findOrCreate(..., function (err, user) { 	       done(err, user);  	     });  	   } 	 ));
This can be set when initializing SlackStrategy or when calling authenticate.
For example when initalizing SlackStrategy:
	passport.use(new SlackStrategy({
	    clientID: '123-456-789’,
	    clientSecret: 'shhh-its-a-secret’
	    callbackURL: 'https://www.example.net/auth/slack/callback',
	    scope: 'identify,read,post,client,admin’,
            team: 'teamID’
 	   }, function(accessToken, refreshToken, profile, done) {
	     User.findOrCreate(..., function (err, user) {
	       done(err, user);
 	     });
 	   }
	 ));

or when calling authenticate / :
   app.get('/auth/slack', slack.passport.authenticate('slack', {'team': ’teamID'}));

nginz/passport-slack,mjpearson/passport-slack