Function Semaphore

Semaphore(permits: number): Semaphore

Creates a new Semaphore with the given capacity.

Parameters

permits: number
The maximum number of concurrent operations allowed. Must be a non-negative integer. Use 0 to disallow any concurrent acquire (acquire will wait forever).

Returns Semaphore

A new Semaphore instance.

Throws

If permits is negative or not an integer.

Example

// Limit to 5 concurrent operations
const sem = Semaphore(5);

// Binary semaphore (equivalent to a value-less Mutex)
const binary = Semaphore(1);

Example

// Task queue: process 2 jobs at a time
const sem = Semaphore(2);

async function processJob(job: Job) {
    return sem.withPermit(async () => {
        return await runJob(job);
    });
}

await Promise.all(jobs.map(processJob));