reducer.js

const initialState = {
  project: "My-App",
  lists: [
    {
      id: 1,
      title: "A Fazer",
      cards: [
        {
          id: 1,
          description: "Comprar Pao"
        }
      ]
    },
    {
      id: 2,
      title: "Fazendo",
      cards: [
        {
          id: 1,
          description: "Comprar Arroz"
        }
      ]
    },
    {
      id: 3,
      title: "Feito",
      cards: [
        {
          id: 1,
          description: "Ler um livro"
        }
      ]
    }
  ]
}

function reducer(state, { type, payload }) {
  switch (type) {
    case 'add':
       return {
        ...state,
         lists: state.lists.concat(payload),
       }
    case 'remove':
      return {
        ...state,
        lists: state.lists.filter(item => item.id !== payload)
      }
    
    case 'update':
      return {
        ...state,
        lists: state.lists.map(item => item.id === payload.id ?
                               { ...item, ...payload } : item)
      }
    default:
       return state
}