please tell me how to correct the error

MongoClient.connect('mongodb://' + config.mongo.host + ':' + config.mongo.port + '/fastdelivery', function(err, db) { ^ TypeError: Cannot read property 'host' of undefined at Object.<anonymous> (C:\nir7\app\app.js:73:48) at Module._compile (module.js:570:32) at Object.Module._extensions..js (module.js:579:10) at Module.load (module.js:487:32) at tryModuleLoad (module.js:446:12) at Function.Module._load (module.js:438:3) at Module.runMain (module.js:604:10) at run (bootstrap_node.js:389:7) at startup (bootstrap_node.js:149:9) at bootstrap_node.js:502:3

    2 answers 2

    You have a config object (probably), but there is no mongo field in it, and therefore config.mongo.host , config.mongo.port also not specified.

       'mongodb://127.0.0.1:27017/fastdelivery'

      better so