Dart
Dart
HTML Canvas
HTML Canvas
Redis
Redis
Bash
Bash
JavaScript
JavaScript
JavaScript
JavaScript

JavaScript Async-Await

Aysnc await operator

function helloWorld() { return new Promise(resolve => { setTimeout(() => { resolve('Hello World!'); }, 2000); }); } async function msg() { const msg = await helloWorld(); console.log('Message:', msg); } msg(); // Message: Hello World! <-- after 2 seconds

Error Handling

let json = '{ "age": 30 }'; // incomplete data try { let user = JSON.parse(json); // <-- no errors console.log( user.name ); // no name! } catch (e) { console.error( "Invalid JSON data!" ); }

Async Await Promises

function helloWorld() { return new Promise(resolve => { setTimeout(() => { resolve('Hello World!'); }, 2000); }); } async function msg() { const msg = await helloWorld(); console.log('Message:', msg); } msg(); // Message: Hello World! <-- after 2 seconds

Resolving Promises

let pro1 = Promise.resolve(5); let pro2 = 44; let pro3 = new Promise(function(resolve, reject) { setTimeout(resolve, 100, 'foo'); }); Promise.all([pro1, pro2, pro3]).then(function(values) { console.log(values); }); // expected => Array [5, 44, "foo"]

Asynchronous

function helloWorld() { return new Promise(resolve => { setTimeout(() => { resolve('Hello World!'); }, 2000); }); } const msg = async function() { //Async Function Expression const msg = await helloWorld(); console.log('Message:', msg); } const msg1 = async () => { //Async Arrow Function const msg = await helloWorld(); console.log('Message:', msg); } msg(); // Message: Hello World! <-- after 2 seconds msg1(); // Message: Hello World! <-- after 2 seconds
Comments
Related