await javascript

1const data = async ()  => {
2  const got = await fetch('https://jsonplaceholder.typicode.com/todos/1');
3  
4  console.log(await got.json())
5}
6
7data();

1function resolveAfter2Seconds() {
2  return new Promise(resolve => {
3    setTimeout(() => {
4      resolve('resolved');
5    }, 2000);
6  });
7}
8
9//async function:
10async function asyncCall() {
11  console.log('calling');
12  const result = await resolveAfter2Seconds();
13  console.log(result);
14  // expected output: 'resolved'
15}
16
17asyncCall();

1function hello() {
2  return new Promise((resolve,reject) => {
3    setTimeout(() => {
4      resolve('I am adam.');
5    }, 2000);
6  });
7}
8async function async_msg() {
9  try {
10    let msg = await hello();
11    console.log(msg);
12  }
13  catch(e) {
14    console.log('Error!', e);
15  }
16}
17async_msg(); //output - I am adam.

1/* Notes:
2	1. written like synchronous code
3    2. compatible with try/catch blocks
4    3. avoids chaining .then statements
5    4. async functions always return a promise
6    5. function pauses on each await expression
7    6. A non promise value is converted to 
8       Promise.resolve(value) and then resolved
9*/
10
11// Syntax
12// Function Declaration
13async function myFunction(){
14  await ... // some code goes here
15}
16  
17// Arrow Declaration
18const myFunction2 = async () => {
19  await ... // some code goes here
20}
21  
22 // OBJECT METHODS
23
24const obj = {
25	async getName() {
26		return fetch('https://www.example.com');
27	}
28}
29
30// IN A CLASS
31
32class Obj {
33	// getters and setter CANNOT be async
34	async getResource {
35		return fetch('https://www.example.com');
36	}
37}
38  

1If the value of the expression following the await operator is not a Promise, it's converted to a resolved Promise.

1The await operator is used to wait for a Promise. It can only be used inside an async function within regular JavaScript code; however it can be used on its own with JavaScript modules.
2