How to use

groupBy

function

in

Array

const composeEntries = (editor, entries: Entry[]): Element[] => {
 return Arr.bind(Arr.groupBy(entries, isIndented), (entries) => {
  const groupIsIndented = Arr.head(entries).map(isIndented).getOr(false);
  return groupIsIndented ? indentedComposer(editor, entries) : outdentedComposer(editor, entries);
 });
}