Function countByFactory

src/Operations.js:376–382

(collection, grouper, context)

}

export function countByFactory(collection, grouper, context) {
  const groups = Map().asMutable();
  collection.__iterate((v, k) => {
    groups.update(grouper.call(context, v, k, collection), 0, (a) => a + 1);
  });
  return groups.asImmutable();
}

export function groupByFactory(collection, grouper, context) {
  const isKeyedIter = isKeyed(collection);