Error in AWS SDK: Uncaught ReferenceError: DOMParser is not defined

[srinathreddydudi]

What versions & operating system are you using?

wrangler 4.40.0

Please provide a link to a minimal reproduction

No response

Describe the Bug

Getting Uncaught ReferenceError: DOMParser is not defined when pushing deployment using wrangler. Seems to be an issue with aws/aws-sdk-js-v3#7347. Not sure if the fix needed here or on AWS SDK repo.

Please provide any relevant error logs

No response

[petebacondarwin]

Yes the problem is here https://github.com/aws/aws-sdk-js-v3/pull/7347/files#diff-a6e2ff9d6fc7622be08357b0aad5edeb5dfd3eb990412c93a440dafff5fa1382R43-R45

Because Wrangler sets the following build conditions when bundling your Worker: ["workerd", "worker", "browser"].
So it will grab the browser entry-point and try to use the DomParser, which does not exist in Workers.

Ideally the library can add an entry-point above the browser one like:

  "workerd": {
    "./dist-es/xml-parser": "./dist-es/xml-parser",
  },
  "browser": { ... }

But you may be able to workaround this by setting the build conditions (i.e. remove the browser condition) for Wrangler via an environment variable:

WRANGLER_BUILD_CONDITIONS= workerd,worker npx wrangler dev

Closing as this is working as expected.

[srinathreddydudi]

But you may be able to workaround this by setting the build conditions (i.e. remove the browser condition) for Wrangler via an environment variable:

WRANGLER_BUILD_CONDITIONS= workerd,worker npx wrangler dev

Could you provide me some documentation around this? I tried the environment variable but still not working and couldn't find any relevant documentation around this. The error is happening when i run wrangler deploy

[petebacondarwin]

There is documentation on build conditions here: https://esbuild.github.io/api/#conditions. It is quite complex and messy.

There is a slight typo in my snippet (unwanted space), also given that the package only provides two exports (browser and react-native) then it might be that imports of "./dist-es/xml-parser" will always end up at the browser one.
It turns out that the browser condition is always active if the platform is set to browser, which I believe is the default. So it is possible that you might need to set WRANGLER_BUILD_PLATFORM to node or neutral. But chances are that this might break something else.
One last thing you might try is to set an alias (see https://developers.cloudflare.com/workers/wrangler/configuration/#module-aliasing). Perhaps something like:

But at the end of the day, I think the real solution is to ask that library to provide a more resilient package.json.

[GwFreak01]

@srinathreddydudi can you lmk what you did to resolve, if fixed? I recently got this error too.

[srinathreddydudi]

@srinathreddydudi can you lmk what you did to resolve, if fixed? I recently got this error too.

I used a polyfill to resolve this. Installed @xmldom/xmldom package and created a polyfill file as below.

// polyfills.js
import { DOMParser as XDOMParser } from '@xmldom/xmldom';
globalThis.DOMParser = XDOMParser;

Then imported the polyfill before importing the aws sdk

// index.js
import './polyfills.js';
import { S3Client, PutObjectCommand } from "@aws-sdk/client-s3";

[SiNONiMiTY]

But you may be able to workaround this by setting the build conditions (i.e. remove the browser condition) for Wrangler via an environment variable:

WRANGLER_BUILD_CONDITIONS= workerd,worker npx wrangler dev

Could you provide me some documentation around this? I tried the environment variable but still not working and couldn't find any relevant documentation around this. The error is happening when i run wrangler deploy

https://github.com/cloudflare/workers-sdk/releases/tag/wrangler%403.78.6

It was included in this release

You might also want to set that variable during deployment for it to work

but the best course of action here is to use the polyfill approach