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Module

x/ayonli_jsext/lock.ts>Mutex

A JavaScript extension package for building strong and modern applications.
ayonli/jsext
Latest
namespace Mutex
import { Mutex } from "https://deno.land/x/ayonli_jsext@v0.9.72/lock.ts";
class Mutex
import { Mutex } from "https://deno.land/x/ayonli_jsext@v0.9.72/lock.ts";

Mutual Exclusion prevents multiple coroutines from accessing the same shared resource simultaneously.

NOTE: Currently, the Mutex instance can not be used across multiple threads, but is considering adding support for parallel threads.

Examples

Example 1

import { Mutex } from "@ayonli/jsext/lock";
import { random } from "@ayonli/jsext/number";
import { sleep } from "@ayonli/jsext/async";

const mutex = new Mutex(1);

async function concurrentOperation() {
    using shared = await mutex.lock();
    const value1 = shared.value;

    await otherAsyncOperations();

    shared.value += 1
    const value2 = shared.value;

    // Without mutex lock, the shared value may have been modified by other
    // calls during `await otherAsyncOperation()`, and the following
    // assertion will fail.
    console.assert(value1 + 1 === value2);
}

async function otherAsyncOperations() {
    await sleep(100 * random(1, 10));
}

await Promise.all([
    concurrentOperation(),
    concurrentOperation(),
    concurrentOperation(),
    concurrentOperation(),
]);

Constructors

new
Mutex(value: T)

Properties

private
[_queue]: (() => void)[]
private
[_value]: T

Methods

lock(): Promise<Mutex.Lock<T>>

Acquires the lock of the mutex, optionally for modifying the shared resource.