Multi Tab Detection

Used to detect multiple tabs being opened. Same tab is defined as having the same origin policy. InPrivate/Incognito tab is treated as a different instance and won't be considered in the multi tab detection of the non (InPrivate/Incognito) tabs. Same origin in the InPrivate/Incognite is considered as its own multiple tabs. In theory, it means you can have 2 separate multi tab detection (one for normal tab and one for InPrivate/Incognito tab) for the same origin.

Inspiration

The idea behind this multi tab detection is based on the stack overflow answer of Sasi Varunan on how to check if a website is open in another tab:

<script type="text/javascript">
    // Broad cast that your're opening a page.
    localStorage.openpages = Date.now();
    var onLocalStorageEvent = function(e){
        if(e.key == "openpages"){
            // Listen if anybody else opening the same page!
            localStorage.page_available = Date.now();
        }
        if(e.key == "page_available"){
            alert("One more page already open");
        }
    };
    window.addEventListener('storage', onLocalStorageEvent, false);
</script>

How to Use

Instantiate MultiTabDetection at the beginning of your website.
Subscribe to either or both NewTabDetectedEvent and/or ExistingTabDetectedEvent.
You can also call the method NumberOfTabsOpened to get the number of tabs opened.

API

Constructor

var multiTabDetection = new MultiTabDetection();

Events

NewTabDetectedEvent

Informs the listener that a new tab has been detected for the same browser session. It also pass in the total number of tabs opened for the same browser session.

ExistingTabDetectedEvent

Informs the listener that an existing tab existed for the same browser session.

ClosedTabDetectedEvent

Informs the listener that a tab for the same browser session has been closed. It also pass in the updated total number of tabs opened for the same browser session.

Properties

NumberOfTabsOpened

Gets the total number of tabs opened. It is recommended to wait for 1 second after receiving existingTabDetectedEvent before calling this property to get the accurate total number of tabs opened.

Sample Implementation

You can find sample implementation of this node module in multi-tab-detection-samples.

Versions

Version	Release Notes
1.1.3	Update packages used by the library based on security advise from GitHub dependabot.
1.1.2	Update packages used by the library based on security advise from GitHub dependabot. Fix https://github.com/uy-andrew/multi-tab-detection/issues/9.
1.1.1	Update packages used by the library based on security advise from GitHub dependabot.
1.1.0	Fix issue where sometimes it does not count properly the correct total number of tabs opened in succeeding tabs.
1.0.3	Fix number of tabs opened count not working (Non-Working Version)
1.0.2	Downgrading the typescript so that it can be compatible with Angular 8 application (Non-Working Version)
1.0.1	Fix the README not showing properly in npmjs website (Non-Working Version)
1.0.0	Initial Commit (Non-Working Version)

Author

Andrew Uy