redux-observable-process-fetch

This library is a redux-observable middleware. And as redux-observable is a middleware itself it is a middleware for middleware.

This middleware add caching, refetching, pre and post loading actions support for async data loading services like Observable.ajax or any other service with signature (...args: Array<any>) => Observable<any>.

Example

The best example is a tests

Initialize redux with redux-observable and redux-observable-process-fetch

import { Observable } from 'rxjs/Observable';
import 'rxjs/add/observable/dom/ajax';
import { createStore, applyMiddleware } from 'redux';
import { reduxObservable, combineDelegators } from 'redux-observable';
import { createFetchProcess } from 'redux-observable-process-fetch';

const ctreateStoreWithReduxObservableMiddleware = (reducer) => {
  const processor = combineDelegators(
    createFetchProcess({ fetch: (type, id) => Observable.ajax(`http://blbla/${type}/${id}`) })
  );
  const middleware = reduxObservable(processor);
  const store = createStore(reducer, applyMiddleware(middleware));
  return store;
};

Create action creator

export const loadMySuperObject = (...args) => ({
  type: FETCH_DATA,
  meta: { type: 'SUPER_OBJECT_LOAD', cache: true },
  payload: args,
});

Use loadMySuperObject as usual in redux.

What you will get

For each action with type FETCH_DATA, like this

const fetchDataAction = {
  type: FETCH_DATA,
  meta: { type: ON_FETCH_SOMETHING_COMPLETE, cache: false },
  payload: [1, 2]
}

It dispatches LOADING_START and LOADING_END actions before data fetch starts and after it end.

On fetch complete it dispatches action

{
  type: fetchDataAction.meta.type,
  payload: fetchResult,
  meta: fetchDataAction.meta
}

and on fetch error

{
  type: fetchDataAction.meta.type,
  payload: error,
  error: true,
  meta: fetchDataAction.meta
}

If FETCH_DATA action meta has cache: false property, and action with same payload and meta.type has already been successfully processed, it does nothing (as data is already in redux store).

It fetch again if there where fetch error at previous call.

If FETCH_DATA action meta has cache: true property, it always fetch data again, cancelling previous FETCH_DATA action with same payload and meta.type.

If such actions are called simultaneously first action does not run at all.

If sequentially action LOADING_CANCEL will be run.

Look at tests for more examples.

Install

npm install --save redux-observable-process-fetch