redux-queue-offline

Queue actions when offline and dispatch them when getting back online.
Working nicely together with redux-optimist-promise.

npm install --save redux-queue-offline

Usage

Step 1: combine your reducers with the offlineQueue reducer

reducers/index.js

import { reducer as offlineQueue } from 'redux-queue-offline'
import { combineReducers } from 'redux'
import todos from './todos'
import status from './status'

export default combineReducers({
  offlineQueue,
  todos,
  status
})

Step 2: Use the offlineQueue middleware

First, import the middleware creator and include it in applyMiddleware when creating the Redux store. You need to call it as a function (See later why on configuration section below):

import { middleware as offlineQueueMiddleware } from 'redux-queue-offline'

const composeStoreWithMiddleware = applyMiddleware(
  offlineQueueMiddleware()
)(createStore)

When used with an async middleware, offlineQueueMiddleware need to be place before it.

Step 3: Mark your actions to be queued with the queueIfOffline meta key

store.dispatch({
  type: 'ADD_TODO',
  payload: {
    text,
    promise: {url: '/api/todo', method: 'POST', data: text}
  },
  meta: {
    queueIfOffline: true
  }
})

When the app is offline, the following actions will be dispatch:

{                                // no need to worry about this one though
  type: 'redux-queue-offline/QUEUE_ACTION',
  payload: {
    type: 'ADD_TODO',
    payload: {
      text,
      promise: {url: '/api/todo', method: 'POST', data: text}
    },
    meta: {
      queueIfOffline: true
    }
  }
}


{
  type: 'ADD_TODO',
  payload: {
    text                       // notice that the `promise` has disappear
  },
  meta: {
    queueIfOffline: true
  }
}

Once getting back online, the following action will be dispatch:

{
  type: 'ADD_TODO',
  payload: {
    text,
    promise: {url: '/api/todo', method: 'POST', data: text}
  },
  meta: {
    skipOptimist: true,       // useful not to apply the optimist update twice
    queueIfOffline: true
  }
}

Step 4: Fire ONLINE and OFFLINE action when changing

The state of the app (online or offline) is stored in the state. To update it, dispatch the ONLINE or OFFLINE actions.

import { ONLINE, OFFLINE } from 'redux-queue-offline'

dispatch({ type: ONLINE })

dispatch({ type: OFFLINE })

You can use the NetworkListener high order component from redux-queue-offline-listener to wrap the redux Provider and automatically dispatch the ONLINE and OFFLINE action when listening to window.on('online') and window.on('offline').

import NetworkListener from 'redux-queue-offline-listener'
import { Provider } from 'react-redux'

const NetworkListenerProvider = NetworkListener(Provider)

ReactDOM.render(
  <NetworkListenerProvider store={store}>
    <MyRootComponent />
  </NetworkListenerProvider>,
  rootEl
)

Configuration

You can configure the name of the reducer (default to offlineQueue) and the fields being deleted from the action when offline (default to payload.promise).

import { middleware as offlineQueueMiddleware } from 'redux-queue-offline'

const composeStoreWithMiddleware = applyMiddleware(
  offlineQueueMiddleware('myOfflineQueueReducerName', ['payload.thunk', 'meta.redirect'])
)(createStore)

Gotcha

DO NOT DISPATCH A PROMISE DIRECTLY (otherwise, queuing will be useless). Do use a middleware to transform a descriptive object ({url: '/api/todo', method: 'POST', data: text}) to a proper promise.

License

MIT