epics.md

Epics

Epics are particularly useful for responding to actions (often described as a "sidecar").

Setup

Examples below assume that you have setup redux-observable middleware so that firebase is available within your epics. Here is an example combineEpics function that adds getFirebase as the third argument along with an epic that uses it:

import { getFirebase } from 'react-redux-firebase'
import { combineEpics } from 'redux-observable'

const rootEpic = (...args) =>
  combineEpics(somethingEpic, notificationEpic)(..args, getFirebase)

// then later in your epics
const somethingEpic = (action$, store, getFirebase) =>
  action$.ofType(SOMETHING)
    .map(() =>
      getFirebase().push('somePath/onFirebase', { some: 'data' })
    )

Debounced Notifications

Debounce is writing to a ref on Firebase such as /notifications (useful so that tons of similar notifications aren't created).

const SEND_NOTIFICATION = 'SEND_NOTIFICATION';

export const notificationEpic = (action$, { getState, dispatch }, { getFirebase }) =>
  action$.ofType(SEND_NOTIFICATION) // stream of notification actions
    .debounceTime(2000) // debounce SEND_NOTIFICATION actions by 2 seconds
    .do((action) => {
      // push the notification object to the notifications ref
      return getFirebase().push('/notifications', action.payload)
    })
    .mapTo({ type: 'EMAIL_NOTIFICATION_CREATED' });