Lock

SlimIO Asynchronous Handler Mutex "Like" Lock. This package has been created to easily lock parallel execution of JavaScript Asynchronous function.

Requirements

• Node.js v14 or higher

Getting Started

This package is available in the Node Package Repository and can be easily installed with npm or yarn.

$ npm i @slimio/lock
# or
$ yarn add @slimio/lock

Usage example

const Lock = require("@slimio/lock");

const asyncLocker = new Lock({ maxConcurrent: 3 });

async function npmInstall() {
    const free = await asyncLocker.acquireOne();
    try {
        await new Promise((resolve) => setTimeout(resolve, 1000));
        console.log("npm install resolved!");
    }
    finally {
        free();
    }
}

// Run 3 per 3 methods
Promise.all([
    npmInstall(),
    npmInstall(),
    npmInstall(),
    npmInstall(),
    npmInstall()
]).then(() => console.log("all done!")).catch(console.error);

API

Properties

declare class Lock {
    public readonly max: number;
    public readonly running: number;
}

Methods

acquireOne(): Promise< () => void >

Create a new lock counter. Return a function that you need to execute to free the counter/lock.

freeOne(error?: Error): void

free an acquired lock (or do nothing if there is no lock acquired yet).

rejectAll(errorMessage?: string): void

Reject all promises and available locks. This will throw an Error for each called acquireOne. The default error is `Lock acquisition rejected!`.

reset(): void

Reset the Object (will reject if any locks or promises are detected active).

License

MIT