This function create a responder that maps actions to responder functions based on action type. A responder function creates Responses.

You don't normally need responders unless you are trying to mock an API endpoint. Internally, fetchAction will let responders field requests instead of sending them to fetch. If no responder matches the action type, the request will be passed to fetch.

Note: responders happen instead of fetch.

responders versus responseHandlers

The names are somewhat confusing but a responder creates responses while a responseHandler handles them. You would normally use a responder to create Response objects, bypassing fetch. If you are trying to handle responses, try a responseHandler.

The full flow of a fetchAction call looks like this:

  1. requestCreator — creates a Request
  2. responder or fetch — creates a Response
  3. responseHandler — receives a Response; must return a Response
  4. transformer — receives the Response.json(); should return a JavaScript object
  5. fatalHandler — receives thrown errors.


import createFetchAction, { handleResponderActions } from 'fetch-actions'
import FETCH_POSTS from '../modules/reddit/constants'
import 'fetch-everywhere'

const responder = handleResponderActions({
  [FETCH_POSTS]: (request, action) => {
    // use the request and action to create a fetch response
    // @see https://developer.mozilla.org/en-US/docs/Web/API/Response/Response
    const data = { whatever: true }
    return new Response(

const fetchAction = createFetchAction({
  // <-- add other handlers here

export fetchAction


import createFetchAction, { handleRequestCreatorActions, handleResponderActions } from 'fetch-actions'
import FETCH_POSTS from '../modules/reddit/constants'
import 'fetch-everywhere'


const requestCreator = handleRequestCreatorActions({
  [FETCH_POSTS]: action => new Request(`https://www.reddit.com/r/${action.payload}.json`)
  [FETCH_FAKE_POSTS]: action => new Request(`https://example.com`)

// let's create a responder to mock our new example endpoint
const responder = handleResponderActions({
  [FETCH_FAKE_POSTS]: (request, action) => {
    // create fake data
    const data = {
      kind: 'Fake',
      data: {
        children: []

    // respond with fake data
    return new Response(JSON.stringify(data))

// add our creator to fetchAction
const fetchAction = createFetchAction({
  responder // <-- responder will override fetch

fetchAction({ type: FETCH_POSTS, payload: 'reactjs' }) // --> resolves to the real reddit data
fetchAction({ type: FETCH_FAKE_POSTS}) // --> resolves to the fake data, bypasses fetch

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