threaded-lock

A Promise based locking system that works between tabs (across multiple threads).

The Problem

In certain situations you may need to share information between different tabs. If you're reading and writing to storage, it's important to make sure that the information being read is thread safe.

The Solution

Local Storage is shared between tabs. By creating a threaded lock object of the same name in multiple tabs, they first check to see if a lock has been claimed. If not, a tab claims it, then double checks to make sure it still owns it. If a lock is already claimed, it checks to see if it's expired. If not it blocks it until either the lock expires or it is released.

Usage

import ThreadedLock from "threaded-lock";

async function doStuff() {
    // First, create a new lock
    const tl = new ThreadedLock("cool-lock");

    await tl.lock();

    // Do some thread safe stuff in any tab
    writeCookie();
    waitOnAPICall();

    // Unlock so other tabs can continue.
    tl.unlock();
}

In another tab

import ThreadedLock from "threaded-lock";

async function doOtherStuff() {
    // First, create a new lock
    const tl = new ThreadedLock("cool-lock");

    await tl.lock();

    readUpdatedCookie();

    // Unlock so other tabs can continue.
    tl.unlock();
}