MongoNetworkError: failed to connect to server [localhost:27017] on first connect [MongoNetworkError: connection 0 to localhost:27017 timed out
    at Socket.<anonymous> (D:\Desktop\node\mongodblearn\07_student_list\node_modules\mongodb\lib\core\connection\connection.js:355:7)     
    at Object.onceWrapper (events.js:427:28)
    at Socket.emit (events.js:321:20)
    at Socket._onTimeout (net.js:478:8)
    at listOnTimeout (internal/timers.js:549:17)
    at processTimers (internal/timers.js:492:7) {
  name: 'MongoNetworkError'
}]
    at Pool.<anonymous> (D:\Desktop\node\mongodblearn\07_student_list\node_modules\mongodb\lib\core\topologies\server.js:438:11)
    at Pool.emit (events.js:321:20)
    at D:\Desktop\node\mongodblearn\07_student_list\node_modules\mongodb\lib\core\connection\pool.js:562:14
    at D:\Desktop\node\mongodblearn\07_student_list\node_modules\mongodb\lib\core\connection\pool.js:995:11
    at callback (D:\Desktop\node\mongodblearn\07_student_list\node_modules\mongodb\lib\core\connection\connect.js:97:5)
    at D:\Desktop\node\mongodblearn\07_student_list\node_modules\mongodb\lib\core\connection\connect.js:124:7
    at _callback (D:\Desktop\node\mongodblearn\07_student_list\node_modules\mongodb\lib\core\connection\connect.js:349:5)
    at Connection.errorHandler (D:\Desktop\node\mongodblearn\07_student_list\node_modules\mongodb\lib\core\connection\connect.js:365:5)   
    at Object.onceWrapper (events.js:428:26)
    at Connection.emit (events.js:321:20) {
  name: 'MongoNetworkError'
}

The above error indicates that Mongodb is not started