db.stats() returns MongoServerError: scale has to be a number

In mongosh run: 

test> db.stats({freeStorage: 1});

MongoServerError: scale has to be a number > 0

Expected: 

Output similar to the runCommand call:

test> db.runCommand({dbStats: 1, freeStorage: 1});

{

 db: 'test',

 collections: 1,

 views: 0,

 objects: 1,

 avgObjSize: 36,

 dataSize: 36,

 storageSize: 20480,

 freeStorageSize: 0,

 indexes: 1,

 indexSize: 20480,

 indexFreeStorageSize: 0,

 totalSize: 40960,

 totalFreeStorageSize: 0,

 scaleFactor: 1,

 fsUsedSize: 46888751104,

 fsTotalSize: 62725623808,

 ok: 1,

 '$clusterTime': {

  clusterTime: Timestamp(

{ t: 1642786653, i: 1 }

),

  signature: {

   hash: Binary(Buffer.from("0000000000000000000000000000000000000000", "hex"), 0),

   keyId: Long("0")

  }

 },

 operationTime: Timestamp({ t: 1642786653, i: 1 })

}