How does the async queue work in Node.js? Node.js uses the event loop with phases (timers, I/O callbacks, idle, poll, check, close callbacks) to manage async tasks.

sync queues (e.g., with libraries like async.queue) allow you to:

• Control concurrency (limit how many async tasks run simultaneously).
• Queue tasks and process them in order.

Example with async library:

const async = require('async');

const queue = async.queue(async (task) => {

wait doWork(task);

}, 2); // concurrency = 2

queue.push({ id: 1 });

queue.push({ id: 2 });

Node.js internally uses libuv’s thread pool for async I/O, but the event loop manages task

scheduling on the single main thread.

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