the page is already visible to the user. Keep in mind that you cannot use await in regular functions. They are built on top of promises and allow us to write asynchronous code in synchronous manners.. Why Async/await? Callbacks can depend on the result of each one which leads to the following: This is what is often known as the pyramid of doom. At the point when the "Async" call is made, the JavaScript execution thread is free to perform any additional client-side processing (although none are shown in the diagram). If you’re using TypeScript v2.3+, you can compile Async Iterators to older versions of JavaScript. Explore asynchronous programming in JavaScript. Using it correctly is easy and looks like this: So we just have to include the async as attribute, just like it works with defer, but more about that later. Async/await is a modern way of writing asynchronous functions in JavaScript. Bei der Rückgabe der „Async“-Methode übernimmt die Rückruffunktion die Ausführung im Thread, und das Add-in kann auf die Daten zugreifen, sie verarbeiten und das Ergebnis anzeigen. Promises are fine, yet in some situations you may end up with a long chain of then/catch. Anyone who tells you differently is either lying or selling something. They will make your code much cleaner and easier to maintain. The Async statement is to create async method in JavaScript.The function async is always return a promise.That promise is rejected in the case of uncaught exceptions, otherwise resolved to the return value of the async function. Now that you have learnt about Promises and how Promises may help you to deal with asynchronous JavaScript code we can go one step further and learn about two new language keywords which have been added to JavaScript with the ES2017 language specification. The async/await has been introduced in ES8. As you can see in this network tab, the app.js is ready much earlier and therefore runs earlier. Async JavaScript gives you full control of which scripts to add an ‘async’ or ‘defer’ attribute to or to exclude to help increase the performance of your WordPress website. If you run above code, then you will get object Promise as a return value.You can access hello message using then() method like below – We can use multiple await statements. But they can still be confusing. Above scenario might be generate the callback hell issue, callback hell condition happening into js application due to poor coding and nested callback method.You can avid callback hell problem using async-await. It can only be used inside an Async function. async is a keyword that can be added before any function. The filter function keeps only the elements that pass a condition. This works well but what happens when there are multiple callbacks? If we now look at the section of the network tab, we see almost the same as when we implemented the whole thing with async. This property reflects the async attribute of the