About @vitejs/plugin-legacy does not support library mode

[gjactat]

Is your feature request related to a problem? Please describe.
I'm a long time user of Vue in a webpack context and i'm giving a try to Vite.
So far It's been a pleasant journey : Dev mode is really impressive !

My project consists of several standalone Vue components that are instantiated on demand from Vanilla Javascript.
This is why they are currently built with the Webpack Library mode which works just fine.

I have successfully built these components with Vite (with dynamic import and everything) and they work juts fine on modern browser.

Describe the solution you'd like
I'd like to also build those components for legacy browsers... And this is currently not allowed (error message : "@vitejs/plugin-legacy does not support library mode").

I'd like to know if there is still hope for this specific use case ?... And I also like to mention that these legacy builds don't have to be as polished as the es ones (considering that they will only be served to a small percentage of our visitors).

While I wish to give the best experience to the vast majority of my users (equipped with modern browsers), I would be fine with monolithic builds, without any code splitting or dynamic imports for legacy browsers. Maybe with something like Rollup's "inlineDynamicImports" ? After all, these legacy builds should vanish eventually.

Describe alternatives you've considered

Additional context
Add any other context or screenshots about the feature request here.

[Jeaciaz]

Would love to see this implemented. As a developer who has to support IE11, Vite and its out-of-the-box speed and ease of use has been a blessing until I learned library mode doesn't support IE11 :(

[stefandesu]

I've been trying to get my library that was built with Vite working with https://observablehq.com, but so far to no avail. I thought maybe a legacy build would help, but unfortunately, that doesn't work at the moment as discussed here. 🤔

[lovasoa]

Hello !
@yyx990803 : what do you think would be needed to get that to work ? I have users on sanipasse.fr who are on old browsers and for whom the site is currently broken. I would be happy to contribute, but have no idea where to start.

[tylerrrkd]

Would love to see this implemented. As a developer who has to support IE11, Vite and its out-of-the-box speed and ease of use has been a blessing until I learned library mode doesn't support IE11 :(

Hope support soon.

[skyweaver213]

Hope support soon.

[lovasoa]

Happy birthday to this issue 🎈🥳

[fychinesepjj]

Hope support soon.

[wenjoy]

IMHO, app which import the lib should care about to bunde it to be capable of old browser. It's not like build a site. So @vitejs/plugin-legacy doesn't need to support some IE 11. Thoughts?

[wenjoy]

I have figured out a solution to bundle lib supporting old browser without dependent @vitejs/plugin-legacy although I insist that lib no need to worry about it.

Here is a sample config, hope to help anyone encountered this:

//vite.config.js
import { babel } from '@rollup/plugin-babel';
...
 plugins: [
    babel({
      babelHelpers: 'runtime',
      extensions: ['.js', '.jsx', '.es6', '.es', '.mjs', 'ts'],
    })
]

//babel.config.js

module.exports = {
  presets: [
    [
      '@babel/env',
      {
        useBuiltIns: 'usage',
        corejs: 3,
      },
    ],
  ],
  plugins: ['@babel/plugin-transform-runtime'],
};

//package.json
  "browserslist": [
    "> 0.5%",
    "not dead"
  ],

[agileago]

@wenjoy ts is ok ? i think esbuild will deal the ts file but babel will not