How to use express-robots-txt - 1 common examples

// So we can check whether we are in the browser or not.  Required for webpack-load-css
//otherwise it will try and transpile CSS into JavaScript.
process.env.BROWSER = false;

const debug = debugLib('slidewiki-platform');

const host = process.env.HOST ? process.env.HOST : '0.0.0.0';
let port = 3000 ;
if(env === 'production'){
    port = process.env.PORT ? process.env.PORT :  3000;
}else{
    port = process.env.PORT ? parseInt(process.env.PORT) + 1 : 3001;
}

const server = express();
server.use(robots(__dirname + '/robots.txt'));
server.use(cookieParser());
server.use(bodyParser.json({limit: '50mb'}));
server.use(bodyParser.urlencoded({limit: '50mb', extended: true}));
server.use(compression());
server.use(favicon(path.join(__dirname, '/favicon.ico')));
server.use('/public', express.static (path.join(__dirname, '/build')));
server.use('/custom_modules', express.static (path.join(__dirname, '/custom_modules')));
server.use('/assets', express.static (path.join(__dirname, '/assets')));
//server.use('/bower_components', express.static (path.join(__dirname, '/bower_components')));
//add external dependencies to be loaded on frontend here:
server.use('/json3', express.static(path.join(__dirname, '/node_modules/json3')));
server.use('/es5-shim', express.static(path.join(__dirname, '/node_modules/es5-shim')));
server.use('/es6-shim', express.static(path.join(__dirname, '/node_modules/es6-shim')));
server.use('/jquery', express.static(path.join(__dirname, '/node_modules/jquery')));
server.use('/sweetalert2', express.static(path.join(__dirname, '/node_modules/sweetalert2')));
server.use('/headjs', express.static(path.join(__dirname, '/node_modules/headjs')));