A function to filter Trello lists based on a label

trello-dashboard-filter.js

const filterCards = (boards, filter) =>
  boards.reduce((result, board) => {
    const cardsResult = board.lists.reduce((cards, list) => {
      if (
        board.closed === false &&
        list.closed === false &&
        (filter.length === 0 ||
          list.name.toLowerCase() === filter.toLowerCase())
      ) {
        return cards.concat(list.cards.filter(card => card.closed === false));
      }
      return cards;
    }, []);

    if (cardsResult.length > 0) {
      result.push({ board: board, cards: cardsResult });
    }
    return result;
  }, []);