next.js/examples/with-freactal/provideState.js

import { provideState, update } from 'freactal'
import { fetchUserRepos } from './githubApi'

export default serverState => provideState({
  initialState: () => ({
    ...serverState,
    ajaxStatus: false
  }),

  effects: {
    setAjaxLoader: update((state, ajaxStatus) => ({ ajaxStatus })),

    fetchGithubReposList: (effects, username, page) =>
      effects.setAjaxLoader(true)
        .then(() => fetchUserRepos(username, page))
        .then((repos) => effects.setAjaxLoader(false).then(() => repos))
        .then((repos) => (state) => ({
          ...state,
          githubReposList: {
            username,
            page,
            repos: state.githubReposList.repos.concat(repos)
          }
        }))
  }
})