​

​

const request = createEffect()

const requestCache = createStore({})

  .on(request.finally, (cache, {params, ...result}) => {

    if (params in cache) return cache

    return {

      ...cache,

      [params]: result,

    }

  })

​

requestCache.watch(cache => {

  request.use(async (id) => {

    const cachedResult = cache[id]

    if (!cachedResult) {

      return fetch('https://example.com')

    }

    if (cachedResult.status === 'fail') {

      throw cachedResult.error

    }

    return cachedResult.result

  })

})