Async Queue Coordination Report

Drain an awaited work queue one item at a time and label the throughput from a deterministic count.

async_queue_coordination.js

const pending = 4;
let drained = 0;
let outcome = "empty";

async function coordinate(count) {
    const queue = Array.from({ length: count }, (_, i) => i + 1);
    while (queue.length > 0) {
        const item = queue.shift();
        await Promise.resolve(item);
        drained += 1;
    }
    if (drained >= 7) {
        outcome = "backlog";
    } else if (drained > 0) {
        outcome = "flowing";
    }
    console.log(`pending=${count} drained=${drained} status=${outcome}`);
}

coordinate(pending);

queue drain An async queue report awaits each item in turn and keeps the drained count scalar, so the drain order never varies.