export function reducer()

in src/providers/RemoteVideoTileProvider/state.tsx [55:111]
50 lines of code
6 McCabe index (conditional complexity)

export function reducer(state: State, { type, payload }: Action): State {
  const { tiles, tileIdToAttendeeId, attendeeIdToTileId, size } = state;

  switch (type) {
    case VideoTileActionType.UPDATE: {
      const { tileId, attendeeId = '' } = payload;
      const tileStr = tileId.toString();
      const isPresent = tileIdToAttendeeId[tileStr];

      if (isPresent) {
        return state;
      }

      const newTiles = [...tiles, tileId];
      const tileIds = {
        ...tileIdToAttendeeId,
        [tileStr]: attendeeId,
      };
      const attendeeIds = {
        ...attendeeIdToTileId,
        [attendeeId]: tileId,
      };

      return {
        tiles: newTiles,
        tileIdToAttendeeId: tileIds,
        attendeeIdToTileId: attendeeIds,
        size: size + 1,
      };
    }
    case VideoTileActionType.REMOVE: {
      const { tileId } = payload;
      const attendeeId = tileIdToAttendeeId[tileId];
      const tileStr = tileId.toString();

      if (!attendeeId) {
        return state;
      }

      const newTiles = tiles.filter((id) => tileId !== id);
      const tileIds = removeProperty(tileIdToAttendeeId, tileStr);
      const attendeeIds = removeProperty(attendeeIdToTileId, attendeeId);

      return {
        tiles: newTiles,
        tileIdToAttendeeId: tileIds,
        attendeeIdToTileId: attendeeIds,
        size: size - 1,
      };
    }
    case VideoTileActionType.RESET: {
      return initialState;
    }
    default:
      throw new Error('Incorrect type in VideoProvider');
  }
}