A semaphore that allows a limited number of concurrent executions of an operation.

import { Semaphore } from "https://deno.land/x/async@v2.1.0/semaphore.ts";

const sem = new Semaphore(5);
const worker = () => {
  return sem.lock(async () => {
    // do something
  });
};
await Promise.all([...Array(10)].map(() => worker()));