HichamBenjelloun · April 30, 2021 23:56 · HichamBenjelloun · Apr 29, 2021
diff --git a/max-concurrent-promises.js b/max-concurrent-promises.js
 let runningPromiseCount = 0;

 const examplePromiseRunnerQueue = new Array(10)
  .fill(0)
  .map((_, idx) => idx)
  .map((idx) => {
    return async () => {
      console.log(
        `[${new Date().toISOString()}] Promise ${idx} will run! \n# of running promises: ${runningPromiseCount}`
      );

      runningPromiseCount++;

      return await new Promise((resolve) => {
        setTimeout(() => {
          resolve(idx);
          runningPromiseCount--;
        }, idx * 1000);
      });
    };
  });

 const run = (promiseRunnerQueue = [], max = promiseRunnerQueue.length) => {
  const executeAndDelegateNextCall = async (promiseRunner) => {
    try {
      await promiseRunner();
    } finally {
      if (promiseRunnerQueue.length === 0) {
        return;
      }

      const nextPromiseRunner = promiseRunnerQueue.shift();
      executeAndDelegateNextCall(nextPromiseRunner);
    }
  };

  promiseRunnerQueue.splice(0, max).forEach(executeAndDelegateNextCall);
 };

 run(examplePromiseRunnerQueue, 10);
	let runningPromiseCount = 0;

	const examplePromiseRunnerQueue = new Array(10)
	.fill(0)
	.map((_, idx) => idx)
	.map((idx) => {
	return async () => {
	console.log(
	`[${new Date().toISOString()}] Promise ${idx} will run! \n# of running promises: ${runningPromiseCount}`
	);

	runningPromiseCount++;

	return await new Promise((resolve) => {
	setTimeout(() => {
	resolve(idx);
	runningPromiseCount--;
	}, idx * 1000);
	});
	};
	});

	const run = (promiseRunnerQueue = [], max = promiseRunnerQueue.length) => {
	const executeAndDelegateNextCall = async (promiseRunner) => {
	try {
	await promiseRunner();
	} finally {
	if (promiseRunnerQueue.length === 0) {
	return;
	}

	const nextPromiseRunner = promiseRunnerQueue.shift();
	executeAndDelegateNextCall(nextPromiseRunner);
	}
	};

	promiseRunnerQueue.splice(0, max).forEach(executeAndDelegateNextCall);
	};

	run(examplePromiseRunnerQueue, 10);