reducer.js

reducer.js

import CONSTANTS from '../constants/';

const initialState = {
    saldo: 0,
    valorTransacao: 0,
    erro: ""
};

let reducerConta = (state = initialState, action) => {
    switch (action.type) {
        case CONSTANTS.CREDITO:
            return { ...state, erro: "", saldo: state.saldo + action.payload.valor };
        case CONSTANTS.DEBITO:
            return { ...state, erro: "", saldo: state.saldo - action.payload.valor };
        case CONSTANTS.SET_VALOR_TRANSACAO:
            return { ...state, erro: "", valorTransacao: action.payload.valorTransacao };
        case CONSTANTS.ERRO_CONTA:
            return { ...state, valorTransacao: 0, erro: action.payload.message };
        default:
            return state;
    }
};
//outra maneira sem usar switch...
let reducerConta = (state = initialState, action) => {
    let fn = {
        [CONSTANTS.CREDITO]() {
            return { ...state, erro: "", saldo: state.saldo + action.payload.valor };
        },
        [CONSTANTS.DEBITO]() {
            return { ...state, erro: "", saldo: state.saldo - action.payload.valor };
        },
        [CONSTANTS.SET_VALOR_TRANSACAO]() {
            return { ...state, erro: "", valorTransacao: action.payload.valorTransacao };
        },
        [CONSTANTS.ERRO_CONTA]() {
            return { ...state, valorTransacao: 0, erro: action.payload.message };
        }
    };

    if (Object.hasOwnProperty.call(fn, action.type)) {
        return fn[action.type]();
    }
    return state;
};