Get MongoDB Databases in a JavaScript Array

To get MongoDB databases in a JavaScript array, you can use runCommand(). Following is the query to get MongoDB databases in a JavaScript array

> use admin;
switched to db admin
> allDatabasesDetails = db.runCommand({listDatabases: 1});

This will produce the following output

{
   "databases" : [
      {
         "name" : "admin",
         "sizeOnDisk" : 847872,
         "empty" : false
      },
      {
         "name" : "config",
         "sizeOnDisk" : 98304,
         "empty" : false
      },
      {
         "name" : "local",
         "sizeOnDisk" : 73728,
         "empty" : false
      },
      {
         "name" : "sample",
         "sizeOnDisk" : 1273856,
         "empty" : false
      },
      {
         "name" : "sampleDemo",
         "sizeOnDisk" : 352256,
         "empty" : false
      },
      {
         "name" : "studentSearch",
         "sizeOnDisk" : 262144,
         "empty" : false
      },
      {
         "name" : "test",
         "sizeOnDisk" : 9527296,
         "empty" : false
      }
   ],
   "totalSize" : 12435456,
   "ok" : 1
}

Following is the query to get total databases:

> allDatabaseName = []
[ ]
> for (var j in allDatabasesDetails.databases) { allDatabaseName.push(dbs.databases[j].name) }

This will produce the following output

7