Get your own Node server
const fs = require('fs');

// Blocking code example
console.log('Start of blocking code');
const data = fs.readFileSync('myfile.txt', 'utf8'); // Blocks here
console.log('Blocking operation completed');

// Non-blocking code example
console.log('Start of non-blocking code');
fs.readFile('myfile.txt', 'utf8', (err, data) => {
  if (err) throw err;
  console.log('Non-blocking operation completed');
});
console.log('This runs before the file is read');

              
Start of blocking code
Blocking operation completed
Start of non-blocking code
This runs before the file is read
Non-blocking operation completed