async await explained code example

Example 1: async await

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

data();

Example 2: async await

async function showAvatar() {

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

  // read github user
  let githubResponse = await fetch(`https://api.github.com/users/${user.name}`);
  let githubUser = await githubResponse.json();

  // show the avatar
  let img = document.createElement('img');
  img.src = githubUser.avatar_url;
  img.className = "promise-avatar-example";
  document.body.append(img);

  // wait 3 seconds
  await new Promise((resolve, reject) => setTimeout(resolve, 3000));

  img.remove();

  return githubUser;
}

showAvatar();

Example 3: how to make an async function

function resolveAfter2Seconds() {
  return new Promise(resolve => {
    setTimeout(() => {
      resolve('resolved');
    }, 2000);
  });
}

//async function:
async function asyncCall() {
  console.log('calling');
  const result = await resolveAfter2Seconds();
  console.log(result);
  // expected output: 'resolved'
}

asyncCall();

Example 4: async await javascript

function hello() {
  return new Promise((resolve,reject) => {
    setTimeout(() => {
      resolve('I am adam.');
    }, 2000);
  });
}
async function async_msg() {
  try {
    let msg = await hello();
    console.log(msg);
  }
  catch(e) {
    console.log('Error!', e);
  }
}
async_msg(); //output - I am adam.

Example 5: async await

async function f() {

  try {
    let response = await fetch('/no-user-here');
    let user = await response.json();
  } catch(err) {
    // catches errors both in fetch and response.json
    alert(err);
  }
}

f();

Example 6: javscript async await explained

// Promise approach

function getJSON(){

    // To make the function blocking we manually create a Promise.
    return new Promise( function(resolve) {
        axios.get('https://tutorialzine.com/misc/files/example.json')
            .then( function(json) {

                // The data from the request is available in a .then block
                // We return the result using resolve.
                resolve(json);
            });
    });

}

// Async/Await approach

// The async keyword will automatically create a new Promise and return it.
async function getJSONAsync(){

    // The await keyword saves us from having to write a .then() block.
    let json = await axios.get('https://tutorialzine.com/misc/files/example.json');

    // The result of the GET request is available in the json variable.
    // We return it just like in a regular synchronous function.
    return json;
}