Redux Pending Effects

🦋 A redux toolkit that tracks your asynchronous redux actions (effects) and informs about the pending state using the selector function

List of supported libraries that process redux effects:

• redux-toolkit
• redux-saga
• redux-promise-middleware

It’s worth mention that redux-pending-effects allows you to code simultaneously with all libraries above.

Problem it solves

Have you ever been in a situation where you need to add a global loader/spinner to any side effect that your application is processing? Perhaps you are using Redux and some third-party library for asynchronous processing, for example, redux-saga / promise middleware? Great, then it should be interesting to you.

Why not handle the pending state manually for each action?

• It is very unpleasant to create separately for this state and add start and end actions for these actions to each request.
• This is an open place to make mistakes because it’s very easy to forget to add or remove these actions.
• It needs to be supported and somehow live with it.

Well, redux-pending-effects does this from scratch:

• tracks your asynchronous code
• collects them in a bunch
• efficiently calculates active pending effects
• provides a selector for information about the current state of application loading
• available for debugging in redux-devtools
• independent of a particular asynchronous processing solution. Can be used simultaneously with redux-saga and redux-toolkit
• replaces redux-thunk in the matters of side effects (not actions chaining) and redux-promise-middleware (essentially uses it out of the box)

Quickstart

Installation

```shell script
npm install redux-pending-effects

<br/>
### Extend reducers
`redux-pending-effects` provides its own state for storing active effects (pending promise phase).
```javascript
import { combineReducers } from 'redux';
import { includePendingReducer } from 'redux-pending-effects';
import { planetReducer as planet } from './planetReducer';
import { universeReducer as universe } from './universeReducer';
const appReducers = {
  planet,
  universe
};
const reducersWithPending = includePendingReducer(appReducers);
export const rootReducer = combineReducers(reducersWithPending);

Configuration

The package provides a single entry point for set up via configurePendingEffects

configurePendingEffects accepts a single configuration object parameter, with the following options:

• promise: boolean (default false) - enable/disable tracking of asynchronous effects that you pass a promise to the payload.
  Yes, if the option enabled, you can pass promise to the payload, that is the way redux-promise-middleware does.
  For details, you can go to read the documentation of redux-promise-middleware
  about how this works.
• toolkit: boolean (default false) - enable/disable tracking of asynchronous effects produced by redux-toolkit
• saga: boolean (default false) - enable/disable tracking of asynchronous effects produced by redux-saga
• ignoredActionTypes: string[] (default []) - list of action types to not track (do not react on actions with these types)

configurePendingEffects returns an object with two properties:

1. middlewares - an array of defined redux middlewares
2. sagaOptions - options for createSagaMiddleware in case you intend to use redux-saga

Example

Let’s show an example with all options enabled.

import { configurePendingEffects } from 'redux-pending-effects';
import { configureStore, getDefaultMiddleware } from '@reduxjs/toolkit';
import createSagaMiddleware from '@redux-saga/core';
import { rootReducer as reducer } from './root.reducer';
import { rootSaga } from './root.saga';
const { middlewares, sagaOptions } = configurePendingEffects({
  promise: true,
  toolkit: true,
  saga: true,
  ignoredActionTypes: ['IGNORED_ACTION_1', 'IGNORED_ACTION_2']
});
const sagaMiddleware = createSagaMiddleware(sagaOptions);
const toolkitMiddlewares = getDefaultMiddleware();
const middleware = [...middlewares, ...toolkitMiddlewares, sagaMiddleware];
export const store = configureStore({ reducer, middleware });
sagaMiddleware.run(rootSaga);

Selector

Just a regular usage of redux selectors

import React from 'react';
import { useSelector } from 'react-redux';
import { selectIsPending } from 'redux-pending-effects';
import { YourApplication } from './YourApplication';
import { AppLoader } from './App.loader';
export const App = () => {
  const isPending = useSelector(selectIsPending);
  return isPending ? <AppLoader ></AppLoader> : <YourApplication ></YourApplication>;
};

Notes

At the moment, this library completely replaces redux-promise-middleware.
In the plans, through the collaboration, expand the API of redux-promise-middleware to reuse their internal API.

Contributing

Contributions are welcome. For significant changes, please open an issue first to discuss what you would like to change.

If you made a PR, make sure to update tests as appropriate and keep the examples consistent.

Contact

Please reach me out if you have any questions or comments.

• GitHub
• Twitter

References

I find these packages useful and similar to this one. So, it’s important to mention them here.

• redux-pending
• redux-pender
• redux-promise-middleware

The main reason why I didn’t choose them: they do one thing, and it’s impossible to add something second to them.

License

This project is MIT licensed.