Mongo.getDBNames()

List Databases

List the available databases for the current MongoDB instance:

db.getMongo().getDBNames()

The db.getMongo() method creates a connection to the instance. Mongo.getDBNames() returns:

[ 'admin', 'config', 'local', 'test' ]

Map Database List to Another Method

Use Mongo.getDBNames() to get a list of collections:

db.getMongo().getDBNames().map(
   name => db.getSiblingDB( name ).getCollectionNames()
)

Example output:

[
   [ 'system.users', 'system.keys', 'system.version' ],
   [
     'settings',
     'tenantMigrationRecipients',
     'system.sessions',
     'transactions',
     'external_validation_keys',
     'image_collection',
     'tenantMigrationDonors',
     'system.indexBuilds'
   ],
   [
     'replset.minvalid',
     'system.views',
     'oplog.rs',
     'replset.initialSyncId',
     'startup_log',
     'system.replset',
     'system.rollback.id',
     'replset.oplogTruncateAfterPoint',
     'replset.election',
     'system.tenantMigration.oplogView'
   ],
   [
     'feedback',
     'inventory',
     'engineers',
     'clothes'
   ]
]

• Mongo.getDBNames() returns a list of databases.

• map defines a function that iterates over the list of databases. Each iteration of map:

  • assigns a database to the name variable,

  • connects to the database currently stored in name using db.getSiblingDB(),

  • returns the collections in the current database using db.getCollectionNames().