JavaScript itself is not async. It's the programs/engines that runs the scripting language that have decided to make it async with callbacks. For example Microsoft JS is not async.
* ES2022? do have some garbage collection hook that uses a callback, so if that makes it into the standard you could say that JS/ES is async. JavaScript itself does not (yet) have any async functions.
Even though there is the async keyword and Promise() there are no async functions nor callbacks in JavaScript itself. For example setInterval and setTimeout is not part of the language and needs to be implemented by the runtime/program that runs the JavaScript.
