Vite async iife

I am writing a userscript in TypeScript that I want to compile with Vite.

Everything needs to be encapsulated in an iife so that the userscript can run self-contained.

If I weren't using top-level await, I could set build.lib.formats = ['iife'] to have it auto-generate an iife.

Since I am using top-level await, how do I make it build an async iife instead?

I discovered that the vite-plugin-top-level-await plugin automatically wraps code in an async IIFE, to serve its original purpose of allowing top-level await. But, we can easily reuse it for this purpose too.

import { defineConfig } from 'vite';
import topLevelAwait from "vite-plugin-top-level-await";

export default defineConfig({
    build: {
        // ...
    },
    plugins: [
        // Wrap in async iife
        topLevelAwait()
    ]
});