vuex-cognito-sync

A Vuex wrapper for Amazon Cognito Sync Manager.

Installation

Install via Yarn or npm:

$ yarn add vuex-cognito-sync
# or... 
$ npm install --save vuex-cognito-sync

Usage

vuex-cognito-sync is a namespaced module. Your app can have multiple Cognito Sync datasets, and synchronize them with Cognito independently.

Create a config file:

// cognito.config.json
{
  "IdentityPoolId": "us-east-1:********-****-****-****-************"
}

Add module to your Vuex store:

import Vue from 'vue'
import Vuex from 'vuex'
import CognitoSync from 'vuex-cognito-sync'
 
Vue.use(Vuex)
 
export default new Vuex.Store({
  modules: {
    myNamespace: new CognitoSync('datasetName')
  }
})

Call init method when bootstrapping your app:

import CognitoSync from 'vuex-cognito-sync'
import config from './cognito.config.json'
 
// optional Cognito login tokens
let logins = {
  'graph.facebook.com': '** token **'
}
 
CognitoSync.init(config, logins)
  .then(() => {
    // do stuff
  })
  .catch((err) => {
    if (err.code === 'NotAuthorizedException') {
      // login token is probably expired
    }
  })

Initialize a datastore and perform initial sync:

this.$store.dispatch('myNamespace/init')
  .then(() => {
    return this.$store.dispatch('myNamespace/sync')
  })

Actions

init

Initialize this module's dataset. Must be dispatched before any other actions.

this.$store.dispatch('myNamespace/init')
  .then((dataset) => {
    // do stuff
  })

put

this.$store.dispatch('myNamespace/put', {
    key: 'someKey',
    value: 'someValue'
  })
  .then(() => {
    // do stuff
  })

remove

this.$store.dispatch('myNamespace/remove', {
    key: 'someKey'
  })
  .then(() => {
    // do stuff
  })

sync

Tell the dataset to synchronize with the Cognito Sync server, and then update the state in Vuex.

this.$store.dispatch('myNamespace/sync')
  .then(() => {
    // do stuff
  })

What's with the `put` & `remove` actions?

It would seem cleaner to use a plugin to update the local Cognito dataset when the Vuex store changes.

But unfortunately, Amazon Cognito Sync Manager performs all operations asynchronously... Even when making localStorage changes. This means a plugin would go against Vuex's rule that mutations must be synchronous, potentially causing race conditions if you make state changes and then dispatch the sync action right away.

If if you have a better idea of how to deal with this, please open an issue and let me know!

TODO

Configurable conflict resolution logic (currently always resolves with remote record)
Add dataset deleted handling
Add datasets merged handling