Install with npm: npm i redux-promise-middleware -S

First, import the middleware and include it in applyMiddleware when creating the Redux store:

import promiseMiddleware from 'redux-promise-middleware';

composeStoreWithMiddleware = applyMiddleware(
  promiseMiddleware
)(createStore);

To use the middleware, dispatch a promise within the payload of the action and specify a types array. You may pass an optional data object. This is dispatched from the pending action and is useful for optimistic updates.

The pending action is dispatched immediately. The fulfilled action is dispatched only if the promise is resolved, e.g., if it was successful; and the rejected action is dispatched only if the promise is rejected, e.g., if an error occurred.

export function myAsyncActionCreator(data) {
  return {
    types: [
      'ACTION_PENDING',
      'ACTION_FULFILLED',
      'ACTION_REJECTED'
    ],
    payload: {
      promise: doSomethingAsyncAndReturnPromise(data),
      data: data
    }
  };
}

The middleware returns a FSA compliant action for both rejected and resolved/fulfilled promises. In the case of a rejected promise, an error is returned.

Licensed MIT. Copyright 2015 Patrick Burtchaell.