fastq example in nodejs. Task queue to run tasks concurrently with concurrency specified. Handle error occurred in worker fn.

try-fastq.js

const fastq = require("fastq");

// sleep function
function sleep(ms) {
  return new Promise((resolve) => setTimeout(resolve, ms));
}

// worker function
async function worker(arg) {
  console.log(`working on task ${arg}`);
  await sleep(1000);
  if (arg === 5) throw Error("bummer!!");
  console.log(`task ${arg} done`);
  return arg * 2;
}

async function run() {
  // initialize a task queue with function to be executed and concurrency
  const taskQueue = fastq.promise(worker, 3);

  const tasksArgs = Array.from(Array(10).keys());

  // array to collect tasks
  const tasks = [];

  tasksArgs.forEach((arg) => {
    // push arg to worker and push the task to tasks array
    tasks.push(taskQueue.push(arg));
  });

  const results = [];

  // collect results
  for (let task of tasks) {
    try {
      const result = await task;
      results.push(result);
    } catch (error) {
      console.warn(error);
      results.push("Failed");
    }
  }

  console.log(results);
}

run();