问AssertionError [ERR_ASSERTION]：在mongodb中需要使用处理程序(func)

EN

/Users/uchitkumar/api/node_modules/mongodb/lib/mongo_client.js:804
          throw err;
          ^

AssertionError [ERR_ASSERTION]: handler (func) is required
    at new AssertionError (internal/errors.js:315:11)
    at _toss (/Users/uchitkumar/api/node_modules/assert-plus/assert.js:22:11)
    at Function.out.(anonymous function) [as func] (/Users/uchitkumar/api/node_modules/assert-plus/assert.js:122:17)
    at process (/Users/uchitkumar/api/node_modules/restify/lib/server.js:1352:20)
    at argumentsToChain (/Users/uchitkumar/api/node_modules/restify/lib/server.js:1361:12)
    at Server.serverMethod [as put] (/Users/uchitkumar/api/node_modules/restify/lib/server.js:1475:21)

server.listen(config.port, function() {

    mongoose.connection.on('error', function(err) {
        console.log('Mongoose default connection error: ' + err)
        process.exit(1)
    })

    mongoose.connection.on('open', function(err) {

        if (err) {
            console.log('Mongoose default connection error: ' + err)
            process.exit(1)
        }

        console.log(
            '%s v%s ready to accept connections on port %s in %s environment.',
            server.name,
            config.version,
            config.port,
            config.env
        )

        require('./routes')

    })

    global.db = mongoose.connect(config.db.uri)

})

server.get('/', function indexHTML(req, res, next) {
    fs.readFile(__dirname + '/../index.html', function (err, data) {
        if (err) {
            next(err);
            return;
        }

        res.setHeader('Content-Type', 'text/html');
        res.writeHead(200);
        res.end(data);
        next();
    });
});