Three ways to use asynchronous in nodejs

* There are 3 ways to use asynchronous in nodejs: callback, promises, async/await

1. Callbacks functions

- Callbacks are functions that are passed as arguments to other functions and are executed when the operation completes.

- Callbacks are commonly used to handle asynchronous operations.

const fs = require('fs');

fs.readFile('myfile.txt', function(err, data) {

if (err) {

console.error(err);

} else {

console.log(data.toString());

}

});

* function(err, data): is callback (is the second parameter of readFile() method)

2. Promises

- Promises represent a value that may not be avaiable

const fs = require('fs/promises');

fs.readFile('myfile.txt')

.then((data) => {

console.log(data.toString());

})

.catch((err) => {

console.error(err);

});

* (data) is promises (is return by method readFile())

3. Async/await syntax

- Async/await is a syntax allows to write asynchronous code that looks and behaves like synchronous code

const fs = require('fs/promises');

async function readFile() {

try {

const data = await fs.readFile('myfile.txt');

console.log(data.toString());

} catch (err) {

console.error(err);

}

}

readFile();

Thank you