Parcel cannot build vega-lite

[ross-pfahler]

🐛 bug report

Parcel cannot build vega-lite without errors.

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

See: https://github.com/ross-pfahler/parcel-2-demos/blob/vega-lite-bug/babel.config.json

{
  "plugins": [
    "@babel/plugin-proposal-class-properties"
  ],
  "presets": [
    "@babel/preset-env",
    "@babel/preset-typescript"
  ]
}

🤔 Expected Behavior

Vega lite should be built.

😯 Current Behavior

@parcel/optimizer-terser: Invalid assignment

    5930 | $parcel$export(module.exports, "debug", () => $ffdfccca23e11389$export$1c9f709888824e05, (v) => $ffdfccca23e11389$export$1c9f709888824e05 = v);
  > 5931 | $parcel$export(module.exports, "message", () => (parcelRequire("7rYOT")), (v) => (parcelRequire("7rYOT")) = v);
  >      |                                                                                                          ^ Invalid assignment
    5932 | 
    5933 | var $10yO6 = parcelRequire("10yO6");

  💡 It's likely that Terser doesn't support this syntax yet.

I believe the error is coming from: https://github.com/vega/vega-lite/blob/master/src/log/index.ts#L5-L6

💁 Possible Solution

Not sure of solution; there is a work around using an alias to alias to the es5 build for now (eg "vega-lite": "vega-lite/build/vega-lite.js")

🔦 Context

Trying to build a project with vega lite.

💻 Code Sample

https://github.com/ross-pfahler/parcel-2-demos/tree/vega-lite-bug.

To reproduce:

yarn install
yarn build

🌍 Your Environment

Software	Version(s)
Parcel	2.0.0
Node	. 14
npm/Yarn	. yarn 1
Operating System	. osx

[mischnic]

I would say this situation of using @babel/preset-env instead of the recommended @parcel/babel-preset-env is unsupported, this causes all kinds of miscompilations and increased build size (because it first transpiles ESM to CJS, and then Parcel has to analyze the CJS). Can you change that?

I guess we should should emphasize this in the warning when using @babel/preset-env.

[ross-pfahler]

Yes, it did work (I removed the babel config completely). We have run into a few other issues using @parcel/babel-preset-env (they are logged), so we can't switch 100% over for all our projects.

As a work around I mentioned we can use the alias property for now which works fine.

I would still consider this a bug as I imagine others could hit snags like this when upgrading to v2, but of course up to y'all on how supported @babel/preset-env should be.

[mischnic]

We have run into a few other issues using @parcel/babel-preset-env (they are logged), so we can't switch 100% over for all our projects.

Did you open/find existing Github issues for them? I didn't even know that there were any problems.

There isn't anything we can do about @babel/preset-env because Parcel cannot control how much is transpiled without @parcel/babel-preset-env.

[JaredSartin]

I am hitting similar, trying to trace what isn't found.

[dorukde]

I ran into the same issue, and I couldn't figure out a way out (outside of --no-minify or --no-optimize).

[devongovett]

Related: #8467, microsoft/TypeScript#50761

[devongovett]

Fixed by #9318 #9330