Working Redux Reducer

working_reducer.js

const initialState = {
  snacks: []
}

const logCaloriesReducer = (state, action) => {
  // check for state undefined to prevent
  // redux from crashing app on load
  if (typeof state === 'undefined') {
    return initialState;
  }

  switch(action.type) {
    case 'LOG_CALORIES':
      const newState = JSON.parse(JSON.stringify(state));
      const indexOfNextSnack = state.snacks.length;
      const newSnack = {
        calories: action.payload.calories,
        time: action.payload.time
      };
      newState.snacks[indexOfNextSnack] = newSnack;
      return newState;
    default:
      return state;

    return state;
  }
};