During my investigation of this issue, I discovered that esbuild employs a more streamlined approach compared to Babel. Rather than hoisting this and arguments, esbuild directly passes the current this and arguments to the function __async, then utilizes apply internally to properly bind them.

Here's a code example demonstrating this approach:

var foo = {
  bar(_0) {
    return __async(this, arguments, function* ({ name }) {
      console.log("arguments.length", arguments.length);
    });
  }
};

This optimization eliminates the hoisting process for this and arguments, though super references still require hoisting. I'm currently evaluating the possibility of adopting esbuild's transformation strategy for our implementation.

Maybe in another PR.

Why isn't this implemented using FnEnvHoister?

🦋 Changeset detected

Latest commit: 96ef752

The changes in this PR will be included in the next version bump.

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

Oh I forgot the comment. @magic-akari Is there a particular reason?

Oh I forgot the comment. @magic-akari Is there a particular reason?

Are you referring to esbuild's approach?
From my observations, esbuild's output tends to be more consistent and simpler than Babel's across various scenarios.
I generally favor simpler implementations as they tend to be easier to maintain and less prone to bugs.

Why isn't this implemented using FnEnvHoister?

Do you mean wasn't? It is implemented using FnEnvHoister now.
I have no idea why it wasn't implemented that way originally. It might have simply been overlooked.

Sorry, you are right. Now it uses the FnEnvHoister and I think the previous implementation is from old days.

Do you mean wasn't? It is implemented using FnEnvHoister now. I have no idea why it wasn't implemented that way originally. It might have simply been overlooked.

That's good.

From my observations, esbuild's output tends to be more consistent

I don't like apply and bind. IIRC they may introduce some nasty problems.