blocking.js

const fs = require("node:fs");
const crypto = require("node:crypto");


console.log("Namaste World");


let a = 4536;
let b = 4864;

// pbkdf2 - password based key derivative function version 2

// all these  sync function never ever have  callback because the LibUv doesn't register a callback because sync function never ever have a callback. The main thread will hold on till it is generating a key

// Sync Function - WILL BLOCK THE MAIN THREAD - DON'T USE IT
crypto.pbkdf2Sync("password", "salt", 50000000, 64, "sha512");
console.log("First Key is generated.");


// Async Function
crypto.pbkdf2("password", "salt", 50000000, 64, "sha512", (err, key) => {
    console.log("Second Key is generated.");
});


// sync function
fs.readFileSync("./file.txt", "utf-8");
console.log("file read successfully");