Function combineChanges

src/compat/firestore/collection/changes.ts:68–76

(current: DocumentChange<T>[], changes: DocumentChange<T>[], events: DocumentChangeType[])

 * of changes.
 */
export function combineChanges<T>(current: DocumentChange<T>[], changes: DocumentChange<T>[], events: DocumentChangeType[]) {
  changes.forEach(change => {
    // skip unwanted change types
    if (events.indexOf(change.type) > -1) {
      current = combineChange(current, change);
    }
  });
  return current;
}

/**
 * Splice arguments on top of a sliced array, to break top-level ===