Simple demonstration how to use Workers on electron main process

fileCheck.js

//tasks/fileCheck.js
const {parentPort, workerData} = require('worker_threads');
const fs = require('fs')
const crypto = require('crypto')
const sendMessage = (type, value) => {
    const msg = {type: type, value: value};
    parentPort.postMessage(msg);
}

let corruptedFiles = [];

const {cwd, files,hashType} = workerData;

files.forEach(file => {
    try{
        sendMessage("StartCheck", {file: file})
        const filePath = cwd + file.path;
        if (fs.existsSync(filePath)) {
            console.info("Checking", filePath)
            let handler = fs.readFileSync(filePath);
            let stats = fs.statSync(filePath)            
            let hash = crypto.createHash(hashType).update(handler).digest("hex");
            if(hash != file.hash){ //Incorrect Hash
                corruptedFiles.push(file);
            }
        }else{//Not found
            corruptedFiles.push(file);
        }
        sendMessage("endCheck", {file: file})
    }catch (err) {
        sendMessage("errorCheck", {err:err,file: file})
    }
});

sendMessage("done", corruptedFiles);

Task.js

//Task.js

const path = require('path');
const fs = require('fs');
const { Worker } = require('worker_threads')

function checkFileHashTask(files, cwd = "./", hashType = 'md5', msgHandler){
    return new Promise((resolve, reject) => {
        const workerData = {cwd: cwd, files:files,hashType:hashType};
      
        //This Work on develop mode running electron . for example, but doesn't im production (electron-builder)
        let worker =  new Worker(path.join(__dirname, 'tasks', fileName), {workerData});
      

        console.info(`Starting Task FileCheck ${worker.threadId}`);
        worker.on('message', msg => {
            if(msg.type == "done"){
                resolve(msg.value)
            }
            if(typeof msgHandler == 'function'){
                msgHandler(msg);
            }
        });
        worker.on('error', reject);
        worker.on('exit', (code) => {
            if (code !== 0)
                reject(new Error(`Checkfiles stopped with exit code ${code}`));
        })
    })

}

//Run the worker:
const fileList  = [
  {"path": "/path/to/cats.gif", hash:"1236546s5d4s6a5d4321123"}
]; //This array will be splited in number of cpus to make paralell hash checking.

checkFileHashTask(fileList, "./", 'md5', msg => {
  console.debug('Received Message', msg);
}).then(corruptedFiles => {
  console.info(`There are ${corruptedFiles.length} file(s)`);
});