A variety of ways to express asynchronous stuff in JS

various-ways-to-do-async.js

// In an async IIFE with await
(async () => {
  const response = await fetch('http://api.open-notify.org/astros.json')
  const json = await response.json()

  console.log(json)
})();

// Using .then()
fetch('http://api.open-notify.org/astros.json')
  .then(response => response.json())
  .then(json => console.log(json));

// As an async function with await
async function fetchJSON(url = '') {
  const response = await fetch(url)
  const json = await response.json()

  return json
};

// Using the function inside an async IIFE with await
(async () => {
  console.log(await fetchJSON('http://api.open-notify.org/astros.json'))
})();

// Using the function inside an async named function, that is called
async function main() {
  console.log(await fetchJSON('http://api.open-notify.org/astros.json'))
};

main();

// Top level await (works in Chrome, Edge, Firefox, …not yet Safari)
const response = await fetch('http://api.open-notify.org/astros.json');
const json = await response.json();

console.log(json);