Takes a function of two parameters. The first is the current key (which
defaults to this._id, but may have been overridden by previous
[Flat]$MapFs) and the second is the document itself. The function must
return a 2-element array containing the new key and new value.
Takes a function of two parameters. The first is the current key (which defaults to
this._id
, but may have been overridden by previous [Flat]$MapFs) and the second is the document itself. The function must return a 2-element array containing the new key and new value.