Details.markdown

for better understanding, I am showcasing a file downloader as worker.js

index.js

const {
    Worker,
    isMainThread,
    parentPort,
    workerData
} = require('worker_threads');
const workerPath = './worker.js'


const workerCreator = (...sendData) => {
    return new Promise((resolve, reject) => {
        const worker = new Worker(workerPath, {
            workerData: sendData,
        });
        worker.on('message', message => {
            if (message === true) {
                worker.terminate();
                resolve(true);
            } else {
                console.log(message)
            }
        });
        worker.on('error', err => {
            worker.terminate();
            reject(err);
        });
        worker.on('exit', code => {
            worker.terminate();
            if (code !== 0) reject(new Error(`Worker stopped with exit code ${code}`));
        });
    })
}
workerArray = Array(2)

//if (isMainThread) {
    let completeData = [
        ["URL", "FILE_NAME"],
        ["URL", "FILE_NAME"],
        ["URL", "FILE_NAME"]
    ];
  
   Promise.all(completeData.map((fileUnit, i) => {
            return workerCreator(fileUnit[0], 'dir/' + fileUnit[1], i.toString() + ".file");
    )).then(success => {
        console.log("Promise.all Successful");
        console.log(success);

    }).catch(err => {
        console.log("\n\n\nError returned");
        console.log(err);

    });
//}

worker.js

const { workerData, parentPort } = require('worker_threads')
const axios = require('axios');
const fs = require('fs');

const data = workerData;


console.log("\n\nINSIDE OF WORKER THREAD");
// console.log(data);

(async (link = data[0], dir = data[1], file = data[2]) => {
    try{
        if(!fs.existsSync(dir + "/" + file)) {
    const {
        data
    } = await axios.get(link, {
        responseType: "stream"
    });
    fs.mkdirSync(dir, {
        recursive: true
    }, err => {
        console.log(err);
    });
    data.pipe(fs.createWriteStream(dir + "/" + file));
    console.log("Download Complete");
    parentPort.postMessage(JSON.stringify(true))

} else {
    console.log("Skipping Download of:\t" + file + "\n")
}
} catch(err) {
    console.log(err)

}

})()