socketsync

a lightweight module to sync JS objects in realtime across tabs / windows of a browser WEB SOCKETS VERSION.

Features

• Uses local storage event emitters to sync objects in realtime across tabs.
• Never calls the tab that the event occurred on.
• Falls back to cookie polling internally if using an unsupported browser (IE 9+ / Edge).
• Isomorphic.
• Tested with mocha.

Install

npm i -S socketsync

How to use

import socketsync from 'socketsync'

/** Create an action that will trigger a sync to other tabs. */
const action = (userID, first, last) => ({ userID, first, last })

/** Create a handler that will run on all tabs that did not trigger the sync. */
const handler = (value, old, url) => {
  console.info(`Another tab at url ${url} switched user from "${old.first} ${old.last}" to "${value.first} ${value.last}".`)
  // do something with value.userID
}

/** Create a synchronizer. socketsync supports N number of synchronizers for different things across your app. */
const usersync = socketsync('user', action, handler)

/** Start synchronizing. */
usersync.start()

/** IE / Edge do not support local storage across multiple tabs. socketsync will automatically fallback to a cookie polling mechanism here. You don't need to do anything else. */
if(usersync.isFallback)
  console.warn('browser doesnt support local storage synchronization, falling back to cookie synchronization.')

/** Trigger an action that will get handled on other tabs. */
usersync.trigger(1, 'jimmy', 'john')

setTimeout(() => {
  /** Trigger another action in 5 seconds. */
  usersync.trigger(2, 'jane', 'wonka')
}, 5000)

setTimeout(() => {
  /** If its still running, stop syncing in 10 seconds. */
  if(usersync.isRunning)
    usersync.stop()
}, 10000)

Documentation

socketsync(key: string, action: (...args) => payload, handler: payload => {}, [opts: Object]): { start, stop, trigger, isRunning, isFallback }

opts

name | type | default | description -------- | -------- | ----------- | --------------- tracing | boolean | false | toggles tracing for debugging purposes logger | Object | console | the logger object to trace to loglevel | string | 'info' | the log level to use when tracing (error, warn, info, trace)

IE / Edge fallback props for cookiesync

name | type | default | description -------- | -------- | ----------- | --------------- pollFrequency | number | 3000 | the number in milliseconds that should be used for cookie polling idLength | number | 8 | the number of characters to use for tracking the current instance (tab) path | string | '/' | The path to use for cookies secure | boolean | false | Whether to set the secure flag on cookies or not (not recommended) httpOnly | boolean | false | Whether to set the http only flag on cookies or not