Installation

First, install the middleware.

npm i redux-promise-middleware -s

Setup

Import the middleware and include it in applyMiddleware when creating the Redux store:

import promise from 'redux-promise-middleware'
​
composeStoreWithMiddleware = applyMiddleware(
  promise,
)(createStore)

Use

Dispatch a promise as the value of the payload property of the action.

const foo = () => ({
  type: 'FOO',
  payload: new Promise()
});

A pending action is immediately dispatched.

{
  type: 'FOO_PENDING'
}

Once the promise is settled, a second action will be dispatched. If the promise is resolved a fulfilled action is dispatched.

{
  type: 'FOO_FULFILLED'
  payload: {
    ...
  }
}

On the other hand, if the promise is rejected, a rejected action is dispatched.

{
  type: 'FOO_REJECTED'
  error: true,
  payload: {
    ...
  }
}

That's it!

Further Reading

• ​Catching Errors Thrown by Rejected Promises​

• ​Use with Reducers​

• ​Optimistic Updates​

• ​Design Principles​

Copyright (c) 2017 Patrick Burtchaell. Code licensed with the MIT License (MIT). Documentation licensed with the CC BY-NC License.