Make it a function method

[Alexsey]

Historically this functionality were provided by libraries. And libraries are usually expose themselves in code as a separate objects. But if this functionality is considered to be added to the language itself - there is no more reason to limit it with the same restrictions

The proposed transformation is actually not so much about Promise as it is about function - it is convertion of regular function to async function. As it is so, more appropriate place for it is Function.prototype and definitely not Promise. In this case naming would be like asAsync and it would tell more about what it actually do

As a free bonus it would allow to naturally pass arguments to the function call

The syntax became:

Promise.try(f.bind(null, arg1, arg2)

vs

f.asAsync(arg1, arg2)

Another free bonus is that it allows to easily obtain an async version of any function by just

const fAsync = f.asAsync.bind(f)

That may provide more separation to data preparation and business logic

[ljharb]

Interesting idea; but this is about Promises. async functions are just functions that always return a Promise (that allow alternative syntax inside them).

The overwhelming ecosystem standard for this is to call it "try" and attach it to Promise; I think that moving it would cause it to be immediately rejected. Separately, I don't agree with your reasoning - the primitive here is Promise, not Function.

[Alexsey]

Well, async functions are not just always return a promise. They also newer throw. And newer-throw is actually the thing you are interesting in as far as I can see from proposal description

Although I understand the point that such change would probably lead to immediate rejection