Examples of dIfferent async patterns in JavaScript

async-patterns.js

/**
 * Разные асинхронные паттерны в JS, решающие одну и ту же задачу
 */

///////////////// callbacks ///////////////////////////////////
function asyncFunction(callback) {
  setTimeout(callback.bind(this, 42), 100);
}

asyncFunction(console.log.bind(this, 'asyncFunction:'));

///////////////// promises ///////////////////////////////////
const promise = new Promise(resolve => {
  setTimeout(resolve.bind(this, 42), 100);
});

promise.then(console.log.bind(this, 'new Promise:'));

///////////////// async/await ////////////////////////////////
async function myFunction() {
  return new Promise(resolve => {
    setTimeout(resolve.bind(this, 42), 100);
  });
}

(async () => {
  console.log('async function', await myFunction());
})();

///////////////// generators w/ async/await /////////////////
function* generatorFabric() {
	yield new Promise(resolve => {
    setTimeout(resolve.bind(this, 42), 100);
  });
}

const generator = generatorFabric();
(async () => {
	for await (const result of generator) {
  	console.log('generator:', result);
  }
})();