npm run start issue

[jeevan449]

todo list RESTful API server started on: 3000
(node:22876) DeprecationWarning: open() is deprecated in mongoose >= 4.11.0, use openUri() instead, or set the useMongoClient option if using connect() or createConnection(). See http://mongoosejs.com/docs/4.x/docs/connections.html#use-mongo-client

events.js:160
throw er; // Unhandled 'error' event
^
MongoError: failed to connect to server [localhost:27017] on first connect [MongoError: connect ECONNREFUSED 127.0.0.1:27017]
at Pool. (/root/jwt/RESTfulAPITutorial/node_modules/mongodb-core/lib/topologies/server.js:336:35)
at emitOne (events.js:96:13)
at Pool.emit (events.js:188:7)
at Connection. (/root/jwt/RESTfulAPITutorial/node_modules/mongodb-core/lib/connection/pool.js:280:12)
at Connection.g (events.js:292:16)
at emitTwo (events.js:106:13)
at Connection.emit (events.js:191:7)
at Socket. (/root/jwt/RESTfulAPITutorial/node_modules/mongodb-core/lib/connection/connection.js:189:49)
at Socket.g (events.js:292:16)
at emitOne (events.js:96:13)
at Socket.emit (events.js:188:7)
at emitErrorNT (net.js:1281:8)
at _combinedTickCallback (internal/process/next_tick.js:80:11)
at process._tickCallback (internal/process/next_tick.js:104:9)
[nodemon] app crashed - waiting for file changes before starting...

[generalgmt]

This is because you did not start your mongodb server. Kindly open a terminal and run mongod