Svelte 5.33.17: crash with unexpected token `with` when importing `isomorphic-dompurify`

[kyoshino]

Describe the bug

After #16098 landed svelte@5.33.17, my Svelte project gets an empty page with an error message in the console: Uncaught SyntaxError: Unexpected token 'with'. That page imports isomorphic-dompurify and I see a difference in the output between the two versions:

<script>
  import DOMPurify from 'isomorphic-dompurify';
</script>

// svelte@5.33.16
import __vite__cjsImport2_isomorphicDompurify 
  from '/node_modules/.vite/deps/isomorphic-dompurify.js?v=9a59877d';
const DOMPurify = __vite__cjsImport2_isomorphicDompurify.__esModule
  ? __vite__cjsImport2_isomorphicDompurify.default
  : __vite__cjsImport2_isomorphicDompurify;

// svelte@5.33.17
import __vite__cjsImport2_isomorphicDompurify 
  from "/node_modules/.vite/deps/isomorphic-dompurify.js?v=0f8559ca";
const DOMPurify = __vite__cjsImport2_isomorphicDompurify.__esModule
  ? __vite__cjsImport2_isomorphicDompurify.default
  : __vite__cjsImport2_isomorphicDompurify with {  }; // unexpected token

I still get an error if I import the sanitize method directly:

<script>
  import { sanitize } from 'isomorphic-dompurify';
</script>

// svelte@5.33.16
import __vite__cjsImport2_isomorphicDompurify
  from "/node_modules/.vite/deps/isomorphic-dompurify.js?v=4270943f"; 
const sanitize = __vite__cjsImport2_isomorphicDompurify["sanitize"];

// svelte@5.33.17
import __vite__cjsImport2_isomorphicDompurify 
  from "/node_modules/.vite/deps/isomorphic-dompurify.js?v=0f8559ca"; 
const sanitize = __vite__cjsImport2_isomorphicDompurify["sanitize"] with {  }; // unexpected token

Reproduction

Repo: https://github.com/sveltia/sveltia-cms

<script>
  import DOMPurify from 'isomorphic-dompurify';
</script>

Logs

System Info

-

Severity

blocking an upgrade

[paoloricciuti]

I can't reproduce with a fresh project, installing DOMPurify and pasting your code in the main root...please provide an actual minimal reproduction, not your whole project.

[kyoshino]

Okay, I’ve just created a minimum reproduction repo.

[paoloricciuti]

Okay, I’ve just created a minimum reproduction repo.

it's private...but yeah i've also used dompurify in the component in my repro

[kyoshino]

Ah damn, just made it public. Using a DOMPurify method wasn’t necessary to reproduce the issue. Just import.

And the error disappears by downgrading with pnpm add svelte@5.33.16.

[shivan-s]

Yes confirmed.

Offending line.

import __vite__cjsImport3_isomorphicDompurify from "/node_modules/.vite/deps/isomorphic-dompurify.js?v=2cd7f2b3"; const DOMPurify = __vite__cjsImport3_isomorphicDompurify.__esModule ? __vite__cjsImport3_isomorphicDompurify.default : __vite__cjsImport3_isomorphicDompurify with {  };

[MotionlessTrain]

That looks like a vite import rewrite to me

Wondering whether vite can’t handle those import …. with statements that svelte now outputs

[paoloricciuti]

It seems like it's dev only...this is the output of vite plugin inspect which adds the offending line, will try to figure out why

[paoloricciuti]

As usual we need to pin latest esrap to actually close this