error: exports is not defined when using ViteDevServer.ssrLoadModule

[yaquawa]

Describe the bug

error: exports is not defined when using ViteDevServer.ssrLoadModule with the following setups:

package.json

{
  "name": "@yaquawa/vite-plugin-ssr",
  "exports": {
    ".": {
      "import": "./dist/index.mjs",
      "require": "./dist/index.cjs"
    },
    "./BootSSRServer": "./dist/BootSSRServer.cjs",
    "./BootSSRClient": "./dist/BootSSRClient.cjs"
  }
}

index.js

{
  name: 'vite-plugin-ssr',
  config: () => ({
    ssr: {
      external: [
        `@yaquawa/vite-plugin-ssr/BootSSRServer`,
        `@yaquawa/vite-plugin-ssr/BootSSRClient`
      ]
    }
  }),

  resolveId (id, importer, options, ssr) {
    if (id !== 'virtual:BootSSR') {
      return
    }

    const bootSSR = `@yaquawa/vite-plugin-ssr/${ssr
      ? 'BootSSRServer'
      : 'BootSSRClient'}`

    return bootSSR
  }
}

so basically, this won't work even if it really should.

import xxx from '@yaquawa/vite-plugin-ssr/BootSSRClient'

Dirty Workaround?

Change the the "exports" field in package.json to *.mjs and return require.resolve(bootSSR) instead of the package name itself works:

package.json

{
  "name": "@yaquawa/vite-plugin-ssr",
  "exports": {
    ".": {
      "import": "./dist/index.mjs",
      "require": "./dist/index.cjs"
    },
    "./BootSSRServer": "./dist/BootSSRServer.mjs",
    "./BootSSRClient": "./dist/BootSSRClient.mjs"
  }
}

index.js

{
  name: 'vite-plugin-ssr',
  config: () => ({
    ssr: {
      external: [
        `@yaquawa/vite-plugin-ssr/BootSSRServer`,
        `@yaquawa/vite-plugin-ssr/BootSSRClient`
      ]
    }
  }),

  resolveId (id, importer, options, ssr) {
    if (id !== 'virtual:BootSSR') {
      return
    }

    const bootSSR = `@yaquawa/vite-plugin-ssr/${ssr
      ? 'BootSSRServer'
      : 'BootSSRClient'}`

    return require.resolve(bootSSR)
  }
}

Is this the intended way to resolve package name(Subpath exports) in the SSR mode..?!

System Info

vite: 2.1.5
node: v14.11.0

Used package manager: yarn

[zzzej]

I solved it temporarly by using createRequire as suggested here #2074 (comment)

This is an example:

import { createRequire } from 'module';
const require = createRequire(import.meta.url);
const cookie = require('cookie');

[furudean]

Duplicate of #2579?

[muellercornelius]

Duplicate of #2579?

yep 👍🏽