block12.javascript

// Sample Redux reducer
function reducer(state = { prices: {} }, action) {
  console.log(`+${Date.now() - startTime}ms`, action);

  switch (action.type) {
    case 'FETCH_STOCK_PRICE_SUCCESS':
      const prices = Object.assign({}, state.prices, { [action.symbol]: action.price });
      state = Object.assign({}, state, { prices });
      console.log('New state', state);
      return state;
    default:
      return state;
  }
}

store.dispatch({ type: 'FETCH_STOCK_PRICE', symbol: 'MDB' });