https://github.com/wingify/across-tabs

JavaScript
Easy communication between cross-origin browser tabs

AcrossTabs - Easy communication between cross-origin browser tabs.

LIVE DEMO

• Features
• Installation
• Flow diagram
• Usage
• API
• Browser support
• Development Stack
• Process
• Scripts
• Contributing
• Roadmap
• Authors
• Copyright and license

Features

1. Safely enables cross-origin communication among different browser tabs. Uses PostMessage API for communication.
2. Easy to hook custom callback at various levels. Eg: executing a custom method in Child's tab on receiving a message from Parent tab.
3. Option to provide data-tab-opener="name" attribute on the target link/btn(which opens up a new tab), so that it remains disable until Child tab initiates a handshake and is received by the Parent tab
4. Fully fledged API to get information regarding the tabs(Parent and Child tabs) and other communication related methods.
5. Exports in a UMD format i.e. library works everywhere.
6. Only 4.11 KB gzipped.

Installation

Via npm

$ npm install across-tabs

Via bower

$ bower install across-tabs

Flow Diagram

• Opener/Parent tab(P) opens up a new Child tab(C).
• C initiates a handshake with the P tab by sending a postMessage.
• P acknowledges the request and sends C it's identity i.e. UUID along with P information.
• This sets up a communication channel between Parent and Child tab.
• Now, P and C can share custom messages with each other.
• Whenever C gets closed/refreshed, P is notified.
• Whenever P is closed/refreshed, all children of P tab gets notified.

Explanation of diagram

• Parent(P) opens CHild tab(C1) at t=1.
• c1a - When C1 initiates a handshake with the Parent.
• P1 - When P receives C1 message.
• P2 - P acknowledges the request and sends the C1 its identity.
• c1b - When C1 receives acknowledgemnet message along with identity from P.

---

Total Tabs Associated: 1 | Opened Tabs: 1 | Closed Tabs: 0

---

• Parent(P) opens CHild tab(C2) at t=10.
• c2a - When C2 initiates a handshake with the Parent.
• P3 - When P receives C2 message.
• P4 - P acknowledges the request and sends the C2 its identity.
• c2b - When C2 receives acknowledgemnet message along with identity from P.

---

Total Tabs Associated: 2 | Opened Tabs: 2 | Closed Tabs: 0

---

• c1c - Tab C1 closes.
• P5 - P is notified about the C1. Parent updates the list.

---

Total Tabs Associated: 2 | Opened Tabs: 1 | Closed Tabs: 1

---

• Parent(P) opens CHild tab(C3) at t=25.
• c3a - When C3 initiates a handshake with the Parent.
• P6 - When P receives C3 message.
• c2c - Tab C2 sends a custom message.
• P7 - When P receives a message from tab C2. It processes it.
• P8 - P acknowledges the request and sends the C3 its identity.
• c3b - When C3 receives acknowledgemnet message along with identity from P.

---

Total Tabs Associated: 3 | Opened Tabs: 2 | Closed Tabs: 1

---

• When Parent Tab P is closed, all the opened tabs are notified about it.

Usage

Create an instance / reference before using.

Opener(Parent) tab*

var config = {
  onHandshakeCallback: function () { ... },
  onPollingCallback: function () { ... }
}
var parent = new AcrossTabs.Parent(config);

Constructor accepts a configurable Object with the following keys.

• heartBeatInterval: The time interval for polling tabs statuses
• removeClosedTabs: Pass it as true to have only opened tabs in the list
• shouldInitImmediately: Pass it as false to create an instance but initialize it later
• onHandshakeCallback: Callback to be called when a successful connection has been established
• onPollingCallback: Callback to be called every time a tab is polled for its status
• origin: whitelist origin for securing postMessage communication. It will discard the malicious messages trying to trick the behavior. Eg. http://example.com

Config Keys	default	accepts
heartBeatInterval	500 msec	A number representing milliseconds
removeClosedTabs	false	Boolean
shouldInitImmediately	true	Boolean
onHandshakeCallback	Undefined	Function as callback
onPollingCallback	Undefined	Function as callback
origin	'*'	String(url)

New(Child tab)

var config = {
  onReady: onReady,
  onInitialize: onInitialize,
  isSiteInsideFrame: false, // dont set if not required
  handshakeExpiryLimit: 4000, // msec
  onParentDisconnect: onParentDisconnect,
  onParentCommunication: onParentCommunication
};
var child =  new AcrossTabs.Child(config);

Constructor accepts a configurable Object with the following keys.

• handshakeExpiryLimit: Time to wait for getting an acknowledgement from Parent window for child's request
• onReady: Callback to be invoked once child instance is ready
• onInitialize: Callback when a child instance is actually initiated
• onParentDisconnect: Callback to be invoked when Parent gets disconnected
• onParentCommunication: Callback to be invoked whenevr Parent communicates with the child tab
• isSiteInsideFrame: If the library is loaded inside an iframe in the child tab, this needs to be set true for maintaining proper window/frame(s) references
• origin: whitelist origin for securing postMessage communication. It will discard the malicious messages trying to trick the behavior. Eg. http://example.com

Config Keys	default	accepts
handshakeExpiryLimit	5000 msec	A number representing milliseconds
isSiteInsideFrame	null	If child tab has actual site in a fram
onReady	Undefined	Function as callback
onInitialize	Undefined	Function as callback
onParentDisconnect	Undefined	Function as callback
onParentCommunication	Undefined	Function as callback
origin	'*'	String(url)

Example is included in the example folder. Vanilla JS and Vue js versions are there to test out. Note: Run npm install if you wish to run vuejs example since the example needs vue-js library to work.

API

Refer above section on how to create an instance before hitting API methods.

Opener Tab(Parent) Methods

• openNewTab

  Saves data in specifed key in localStorage. If the key is not provided, the library will warn. Following types of JavaScript objects are supported:

  Parameter	Description
  config	For opening a new tab i.e. url and windowName

    parent.openNewTab({url: 'http://example.com', windowName: 'AcrossTab'});
  

• enableElements

  Links / buttons can be given a data attribute: data-tab-opener="name". On clicking, the library finds elements with that attribute and adds disabled="disabled" attribute to that element. The disabled attribute is removed once the Child tab communicates back to the opener i.e. Parent. Though, this method is called internally but can also be invoked(may be within a timer) to be on a safer side.

    parent.enableElements();
  

• getAllTabs

  Returns the list of all the tabs. If removeClosedTabs: true is provided while instantiating, it will return only the opened tabs as closed tabs would be removed.

    parent.getAllTabs()
  

• getOpenedTabs

  Returns the list of all opened tabs.

    parent.getOpenedTabs();
  

• getClosedTabs

  Returns the list of all closed tabs. If removeClosedTabs: true is provided while instantiating, it will return empty list as closed tabs would be removed.

    parent.getClosedTabs();
  

• closeAllTabs

  Closes all the opened tabs.

    parent.closeAllTabs()
  

• closeTab

  Closes a particular tab whose id is provided.

  Parameter	Description
  id	id of the tab to be closed

    parent.closeTab('57cd47da-d98e-4a2d-814c-9b07cb51059c');
  

• broadCastAll

  Sends a same message to all the opened tabs.

  Parameter	Description
  msg	msg to be ent

    parent.broadCastAll('Hello my dear Child! A greeting from Parent.'});
  

• broadCastTo

  Sends a message to a particular opened tab.

  Parameter	Description
  id	id of the tab to send a msg
  msg	msg to be ent

    parent.broadCastTo('57cd47da-d98e-4a2d-814c-9b07cb51059c', 'Hey! Can you run the script: worker.js? Thanks!');
  

New Tab(Child) Methods

• getTabInfo

  Return id, name and parentName of the child tab.

    child.getTabInfo();
  

• sendMessageToParent

  Sends a message to the Parent tab.

  Parameter	Description
  msg	msg to be ent

    parent.sendMessageToParent('Hey Parent! I\'m done with my work.');
  

Browser Support

Tested in Chrome and Firefox.

Development Stack

• Webpack based src compilation & bundling and dist generation.
• ES6 as a source of writing code.
• Exports in a UMD format so the library works everywhere.
• Linting with ESLint.
• ES6 test setup with Karma, Jasmine and isparta.
• Test covergae with Istanbul and Coveralls.

Process

ES6 source files
       |
       |
    webpack
       |
       +--- babel, eslint
       |
       o--- tests and covergae
       |
  ready to use
     library
  in UMD format

Scripts

• npm run build - produces production version(minified) of the library under the dist folder
• npm run dev - produces development version(unminified) of the library and runs a watcher to detect file changes.
• npm run test - well ... it runs the tests :)

Contributing

1. Fork the repo on GitHub.
2. Clone the repo on machine.
3. Execute npm install and npm run dev.
4. Create a new branch <fix-typo> and do your work.
5. Run npm run build to build dist files and npm run test to ensure all test cases are passing.
6. Commit your changes to the branch.
7. Submit a Pull request.

Roadmap

• Having a Queue mechanism to deal with loads of async events.
• Promise based Parent-Child communication. Will help in sending window specific data to and fro apart from custom data messages.
• E2E testing so that the behavior can be tested automatically.
• Maintaining and adding more enhancements as and when required. Open to everyone's suggestions.

Authors

Varun Malhotra @softvar

Copyright and license

The MIT license (MIT)

Copyright (c) 2017-2018 Wingify Software Pvt. Ltd.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.