Parcel 2 build failing with importScripts() is not supported in module workers.

[jessabyrne]

🐛 bug report

The build passes with parcel build public/index.html
but when I run parcel public/index.html I get the below error:

🚨 Build failed.

@parcel/transformer-js: importScripts() is not supported in module workers.

  /Users/jessabyrne/projectrepos/project/node_modules/@loaders.gl/loader-utils/dist/esm/lib/library-utils/library-utils.js:66:12
    65 | 
  > 66 |   return "modules/".concat(moduleName, "/src/libs/").concat(library);
  >    |            ^
    67 | }
    68 | 

It seems to get far along but fails near the end. I've tried clearing both the .cache and .parcel-cache as well as removing node_modules and reinstalling.

This happened after making some changes to fix other errors:

1. changing <script async src="../src/index.tsx" type="text/javascript"></script> to <script async src="../src/index.tsx" type="module"></script>

   2. Changing

          navigator
            .serviceWorker
            .register('service-worker.js')

to

          navigator
            .serviceWorker
            .register(new URL('service-worker.js', meta.url))

🎛 Configuration (.babelrc, package.json, cli command)

package.json

    "@parcel/transformer-raw": "^2.0.0-nightly.755",
    "@parcel/transformer-typescript-tsc": "^2.0.0-nightly.755",
    "parcel": "^2.0.0-nightly.753",

.parcelrc

{
  "extends": "@parcel/config-default",
  "transformers": {
    "*.{ts,tsx}": ["@parcel/transformer-typescript-tsc"],
    "*.{jpg,png,svg}": ["@parcel/transformer-raw"]
  }
}

babel.config.json

{
  "presets": [
    "@babel/preset-env",
    "@babel/preset-react",
    "@babel/preset-typescript"
  ]
}

🤔 Expected Behavior

task should build

😯 Current Behavior

build fails

💁 Possible Solution

Could be related to this issue: #5021
also perhaps this PR #6531

🌍 Your Environment

Software	Version(s)
Parcel	2.0.0-nightly.753
Node	v16.3.0
npm/Yarn	7.15.1
Operating System	osx Big Sur

[mischnic]

This was an intentional change: #6536 (comment)

This comes from https://github.com/visgl/loaders.gl/blob/4323541bb8f0a5402e4ac28f8068e504c493dac7/modules/worker-utils/src/lib/library-utils/library-utils.ts#L86

We might have to only error if this is in user code and just ignore it in node_modules. @devongovett ?

[devongovett]

That would result in broken code. Chrome will throw at runtime on importScripts inside module workers. Parcel is just raising the error at build time. That code should be replaced with a dynamic import() instead.