There is an article AsyncFunction - JavaScript on MDN. It shows the following snippet:
new AsyncFunction([arg1[, arg2[, ...argN]],] functionBody)
Yet in both Mozzila Firefox 55 and Google Chrome, this constructor is not defined at all:
I found out that (async function() {}).constructor really is AsyncFunction, but why can't I see it in global scope?
As mentioned in the Mozilla docs "Note that AsyncFunction is not a global object."
Therefore you can't access it as a property of the window object like other global constructors. It must be obtained by interrogating an instance of an async function:
From the docs:
const AsyncFunction = Object.getPrototypeOf(async function(){}).constructor;
The documentation itself is confused so it's no wonder that people get confused as well.
MDN docs tell us that AsyncFunction is not a global object, and yet they list it in the Global Objects reference! Oops!
This leads to unexpected behavior. This works:
> f1 = function () {};
[Function: f1]
> f1 instanceof Function
true
But this doesn't:
> f2 = async function () {}
[AsyncFunction: f2]
> f2 instanceof AsyncFunction
ReferenceError: AsyncFunction is not defined
I wrote an unexposed module that you can use:
It basically works like the example in the answer by Patrick but you don't have to remember it.
See also this question for more info:
