When you list results, you can add a separator between each element listed. Use the AQL ->sep() service to do so. Note that you can use ->sep('\n') to start a new line after each entry

Example

The following expression returns a list of all elements in the given document that have the property items and begin with F. The elements are separated by a comma followed by a space.

{m:DocumentName.items->select(x | x.name.startsWith('F'))->sep(', ')}