export function checkout() {
  return (dispatch, getState) => {
    return Promise.resolve()
      .then(() => {
        dispatch({ type: 'CHECKOUT_REQUEST' });
        const state = getState();
        if (!state.cart.items) {
          throw Error('No items to checkout');
        }
      })
      .then(() => (
        dispatch({ type: 'CHECKOUT_SUCCESS' })
      ))
      .catch(error =>
        dispatch({ type: 'CHECKOUT_FAILURE', error })
      )
  }
}