jscoop

JavaScript Cooperative Multitasking Locks and Jobs Processing

This is port of Python's asyncio locks, futures and queues modules along with batch processing routines.

Compatibility

• Browsers >= Good
• NodeJS >= 14 (some versions of 13 too)

Usage

NodeJS

To use this code in NodeJS, import the jscoop module to get all the available functionality, or you can selectively import the sub modules, such as jscoop/locks, jscoop/queues, etc. See the src directory or src/coop.mjs for details.

import * as coop from 'jscoop';

(async function() {
    const sem = new coop.Semaphore(2);
    await sem.acquire();
    await sem.acquire();
    await sem.acquire(); // blocks
})();

Browser

For a browser you need to place the files somewhere that your web server can find them and import the full path to the coop.mjs file, or one of the other submodules if you only want some of the functionality.

<script type="module">
    import * as coop from 'jscoop/src/coop.mjs';

    (async function() {
        const sem = new coop.Semaphore(2);
        await sem.acquire();
        await sem.acquire();
        await sem.acquire(); // blocks
    })();
</script>

Examples

jobs.UnorderedWorkQueue - Node

import * as jobs from 'jscoop/jobs';

const bufWork = new jobs.UnorderedWorkQueue({maxPending: 10});

async function sleep(ms) {
    await new Promise(resolve => setTimeout(resolve, ms));
}

async function producer() {
    for (let i = 0; i < 200; i++) {
        // Enqueue a random sleep that returns it's start order.
        await bufWork.enqueue(sleep(Math.random() * 1000).then(() => i));
        console.info('Added to queue', i);
    }
}

async function consumer() {
    for await (const i of bufWork) {
        console.info('Consumed finished result', i);
    }
}

(async () => {
    await Promise.all([producer(), consumer()]);
    console.info("Job compete");
})();

locks.Lock - Browser

import * as locks from 'jscoop/src/locks.mjs';

(async () => {
    const lock = new locks.Lock();
    await lock.acquire();
    lock.release();
    await lock.acquire();
    await lock.acquire(); // blocks
})();

queues.Queue - Node

import * as queues from 'jscoop/queues';

(async () => {
    const q = new queues.Queue();
    q.put(1);
    q.put(2);
    await q.get(); // 1
    await q.get(); // 2
    await q.get(); // blocks
})();