Bundle library with externalized dependencies and Vite?

[florianmartens]

I'm trying to publish a browser focused type:module (esm) library to npm. I'm using vite's library mode with the following config:

export default defineConfig({
  css: {
    postcss: {
      plugins: [tailwindcss, autoprefixer, tailwindcss],
    },
  },
  build: {
    lib: {
      entry: resolve(__dirname, "src/index.ts"),
      name: "lib_name",
      fileName: "lib_name",
    },
    rollupOptions: {
      output: [
        {
          dir: "dist/browser",
          name: "global_name",
          format: "iife",
          plugins: [],
        },
        {
          dir: "dist/esm",
          format: "esm",
          entryFileNames: "index.js",
          sourcemap: true,
        },
      ],
      external: ["@uppy/core"],
    },
  },
  plugins: [dts({ rollupTypes: true })],
});

Ideally, I don't even want to bundle into one big file (but that's a different topic - preserveModules is not the solution here).

My understanding is that since my dependencies are clearly stated in package.json I do not need to bundle them. However, by default vite bundles everything and the resulting .mjs file contains no import statements.

While this is not a big deal, it seems inefficient. Consumers need to install all dependencies anyway - why have the code twice?

How can I change my config so that external dependencies are imported rather than bundled? This seems to be vite's default and I can't quite understand why that is.

Things I've tried

Use external rollout option as a function external: (id: string) => { return /^node_modules/.test(id)} as well as with values ["@uppy/core"]

[hi-ogawa]

Did you check this discussion? It shows a few ideas to put package.json's dependencies into rollupOptions.external.

• Library mode: How should I manage external dependencies? #6198

I don't know either why Vite doesn't do this default, but considering it's rather simple to just copy dependencies into rollupOptions.external, it might not be necessary for Vite to act on this.

[florianmartens]

Thanks for linking the discussion here! That was super helpful!