The ns variable is initialized here and can be undefined depending on whether the command is made using 'shardCollection' or 'shardcollection' – uppercase versus lowercase for the c --, both of which are legal calls.

If the cmdObj is

{shardCollection: 'foo.bar'.....}

, then ns = cmdObj.shardCollection is defined, and the code works.

However, if cmdObj is

{shardcollection: 'foo.bar'....}

, with a lowercase c, then ns = cmdObj.shardCollection is undefined, because javascripts discriminates upper and lower case.