actions.js

import api from './api';

export const ADD_PHOTOS = 'Photos/ADD_PHOTOS';

export function addPhotos(photos) {
  return {
    type: ADD_PHOTOS,
    payload: photos,
  };
}

export function fetchPhotos() {
  return async function(dispatch) {
    const { data: photos } = await api.fetchPhotos();
    dispatch(addPhotos(photos));
  };
}