<script async src="script.js"></script>

(async () => {

  let response = await fetch('/article/promise-chaining/user.json');

  let user = await response.json();

  ...

})();

​

// (BONUS CODE) await with promise

await new Promise(resolve => setTimeout(resolve, 1000))

console.log('Hello!') // 1 seconds after sended console.log

const foo = async () => {

   await// do something

}

// OR

async function foo() {

  await// do something

}

<script src="demo_async.js" async></script>

//ORIGINAL

//each .then() returns a promisse and can be chained. The .then() will run after the previous one has finished. It emulates an async/await behavior.

​

fetch('https://jsonplaceholder.typicode.com/users')//fetch the content

  .then((response) => response.json())//then use that content and convert it to a javascript object

  .then(users => {

    const firstUser = users[0];

    console.log(firstUser);

    return fetch('https://jsonplaceholder.typicode.com/posts?userId=' + firstUser.id);

  })//then return the content from posts related to that user ID

  .then((response) => response.json())//then use that content and convert it to a javascript object

  .then(posts => console.log(posts));//then log the result

​

​

//ASYNC/AWAIT

const myAsyncFunction = async () => {//define that this will be asynchronous

  const usersResponse = await fetch('https://jsonplaceholder.typicode.com/users');//wait for the fecth result and put it in the variable

  const users = await usersResponse.json();//wait for the previous item to be done, transform it into a javascript object and put it in the variable

  const secondUser = users[1];

​

  console.log(secondUser);//then log the result

​

  const postsResponse = await fetch('https://jsonplaceholder.typicode.com/posts?userId=' + secondUser.id);//wait for the previous item to be done, wait for the fecth result and put it in the variable

  const posts = await postsResponse.json();//wait for the previous item to be done, transform it into a javascript object and put it in the variable

​

  console.log(posts);//then log the result

}

​

myAsyncFunction();

//Async function (JAVASCRIPT)

//async function have 1 main purpose:

​

//Being able to use 'await' in a function

function example() {

return await fetch('https://mysite.com/api'); //error

}

​

async function smartexample() {

return await fetch('https://mysite.com/api'); //mhmm!

}

async function getData() {

     const [error, response] ?= await fetch("https://api.example.com/data");

     if (error) return handleError(error);

     return response;

   }

function myFunction() {

  return Promise.resolve("Hello");

}

const asyncExample = async () => {};