nl_tokens: * @method groupBy ( <map > [ fn ] ) @returns Object @short Groups the array by <map > . @extra Will return an object with keys equal to the grouped values . <map > may be a mapping function or a string acting as a shortcut . Optionally calls [ fn ] for each group . @example
pl_tokens: function ( map , fn ) { var arr = this , result = { } , <mask> ; arrayEach ( arr , function ( el , index ) { key = transformArgument ( el , map , arr , [ el , index , arr ] ) ; if ( ! result [ key ] ) result [ key ] = [ ] ; result [ key ] . push ( el ) ; } ) ; if ( fn ) { iterateOverObject ( result , fn ) ; } return result ; }