How to expose bundle as window variable?

[mikaelkarlsson-se]

Hello there 👋
I'm trying to migrate a Webpack setup to Vite and I've got stuck on how to expose the bundle in a window variable. In the old setup I utilized output.type = "window" in Webpack (docs) which would produce window.MyName = ... and I want to do the exact same thing using Vite. Anyone know how to (if it's even possible)?
The only solution I see right now is to manually define window.SomeThing = ... in my entry but I have multiple entries (building one bundle per client) so I find that cumbersome and risky, it's much better solved in the build.

Previous Webpack setup:

export default { theKittenSays: () => "meow" }
...
library: {
    type: "window",
    name: LearnAboutAnimals,
    export: "default",
},
...
window.LearnAboutAnimals.theKittenSays() // -> "meow"

I've fiddled around a lot both with the Vite lib mode as well as using format = "iife" in rollupOptions.output but without success. The iife output in conjunction with adding name should at least create a var as far as I can understand but that is not happening.
Current try:

export default { theKittenSays: () => "meow" }
...
rollupOptions: {
  input: {
    [client]: path.resolve(__dirname, `src/clients/${client}/entry.ts`),
  },
  output: [
    {
      format: "es",
      entryFileNames: "learn-about-animals.es.js",
      assetFileNames: "assets/[name].[ext]",
      dir: `dist/${client}`,
    },
    {
      format: "iife",
      name: "LearnAboutAnimals",
      entryFileNames: "learn-about-animals.js",
      assetFileNames: "assets/[name].[ext]",
      dir: `dist/${client}`,
    },
  ],
},
...

[sapphi-red]

Vite sets preserveEntrySignatures: false by default for non-lib mode build (since normally you won't care about the export for apps). Putting build.lib: {} or rollupOptions.output[1].preserveEntrySignatures: "exports-only" would make the var exist.

[mikaelkarlsson-se]

Ok, thanks for clearing that out 🤝

[mikaelkarlsson-se]

So after some more trial and error and reading of documentation I've finally managed to understand this. There are two ways of doing what I want:

1. Use Vite lib mode and provide the name property, like this:

lib: {
  entry: "some-entry.ts",
  formats: ["iife"],
  name: "TheName" // -> window.TheName
}

2. Assign the variable to window yourself 🔧