{disambiguate=JavaScript}

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/async_function

`async` is all present in <JavaScript> for two reasons:
* you make network requests all the time
* JavaScript is single threaded, so if you are waiting for a network request, the UI freezes, see remarks on the deprecation of synchronous HTTP request at: https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/Synchronous_and_Asynchronous_Requests

However, it is also <Hell>: <how to convert async to sync in JavaScript>.


`async`

<code>async</code> (JavaScript)

{c}
{wiki}

Wellhttps://stackoverflow.com/questions/8775262/synchronous-requests-in-node-js[Sync], if you are gonna usehttps://stackoverflow.com/questions/8775262/synchronous-requests-in-node-jsp[Sync] this <JavaScript>[wonky language] thing inhttps://stackoverflow.com/questions/8775262/synchronous-requests-in-node-js[Sync] one place, you might as well usehttps://stackoverflow.com/questions/8775262/synchronous-requests-in-node-js[Sync] it everywherehttps://stackoverflow.com/questions/8775262/synchronous-requests-in-node-js[Sync] and make it more decent. See also: <how to convert async to sync in JavaScript>.

Their CLI debugger is a bit crap compared to GDB, basic functionality is either lacking or too verbose:
* https://stackoverflow.com/questions/65493221/how-to-break-at-a-specific-function-or-line-with-the-node-js-node-inspect-comman
* https://stackoverflow.com/questions/70486188/how-to-break-on-uncaught-exception-on-the-node-js-node-inspect-command-line-debu Some operations are only possible on the browser debug UI...
Documentation at: https://nodejs.org/dist/latest-v16.x/docs/api/debugger.html


Node.js

<God>, it's impossible! You just have to convert the entire fucking call stack all the way up to async functions. It could mean refactoring hundreds of functions.

To be fair, there is a logic to this, if you put yourself within the crappiness of the <JavaScript> threading model. And <Python> is not that much better with its <Global Interpreter Lock>.

The problem is that async was introduced relatively late, previously we just had to use infinitely deep callback <tree (data structure)>[trees], which was worse:
``
myAsync().then(ret => myAsync2(ret).then(ret2 => myAsync3(re3)))
``
compared to the new infinitely more readable:
``
ret = await myAsync()
ret2 = await myAsync2(ret)
ret3 = await myAsync3(ret3)
``
But now we are in an endless period of transition between both worlds.

It is also worth mentioning that callbacks are still inescapable if you really want to fan out into a non-linear dependency graph, usually with `Promise.all`:
``
await Promise.all([
  myAsync(1).then(ret => myAsync2(ret)),
  myAsync(2).then(ret => myAsync2(ret)),
])
``

Bibliography:
* https://stackoverflow.com/questions/21819858/how-to-wrap-async-function-calls-into-a-sync-function-in-node-js-or-javascript
* https://stackoverflow.com/questions/9121902/call-an-asynchronous-javascript-function-synchronously
* https://stackoverflow.com/questions/47227550/using-await-inside-non-async-function
* https://stackoverflow.com/questions/43832490/is-it-possible-to-use-await-without-async-in-js
* https://stackoverflow.com/questions/6921895/synchronous-delay-in-code-execution

And then, after many many hours of this work, you might notice that the new code is way, way way slower than before, because making small functions `async` has a large performance impact: https://madelinemiller.dev/blog/javascript-promise-overhead/[]. Real world case with a 4x slowdown: https://github.com/ourbigbook/ourbigbook/tree/async-slow[].

Anyways, since you Googled here, you might as well learn the standard pattern to convert callbacks functions into async functions using a promise: https://stackoverflow.com/questions/4708787/get-password-from-input-using-node-js/71868483#71868483

\Image[https://web.archive.org/web/20241129001302im_/https://miro.medium.com/v2/resize:fit:828/format:webp/0*-sXUj7txIyw9LX_F]
{title=async function #Teletubbies meme}
{description=TODO find original source.}
{height=800}
{source=https://andrewzuo.com/async-await-is-the-worst-thing-to-happen-to-programming-9b8f5150ba74}


Ciro Santilli @cirosantilli 37

 Incoming links: How to convert `async` to sync in JavaScript

Ciro Santilli @cirosantilli 37

 Incoming links: How to convert async to sync in JavaScript

 Incoming links: How to convert `async` to sync in JavaScript