.proxyrc.js refuses to work with ES6 ("type" = "module") node projects.

[chriseaton]

🐛 bug report

When trying to run parcel in a "type": "module" node package, the .proxyrc.js refuses to function, getting treated as common js to a degree. Renaming to .proxyrc.cjs or .proxyrc.mjs appears to be unsupported and are never picked up. This basically makes it impossible to leverage another es6 module in the .proxyrc.js. Attempting to utilize the import(...) function available in modern node causes issues. I attempted to simply change the extension in the Server parcel class to use cjs or mjs but both resulted in some JSON parsing error.

{
"type": "module"
}

none

🤔 Expected Behavior

Support .proxyrc.js in type=module node projects, or alternatively support loading mjs/cjs .proxyrc files.

😯 Current Behavior

Errors on startup when the configuration attempts to load.
When trying to use type module:

TypeError [ERR_VM_DYNAMIC_IMPORT_CALLBACK_MISSING]: A dynamic import callback was not specified.
    at new NodeError (node:internal/errors:371:5)
    at importModuleDynamicallyCallback (node:internal/process/esm_loader:39:9)
    at module.exports (/app/.proxyrc.cjs:3:13)
    at Server.applyProxyTable (/app/node_modules/@parcel/reporter-dev-server/lib/Server.js:397:7)
    at async Server.start (/app/node_modules/@parcel/reporter-dev-server/lib/Server.js:421:5)
    at async Object.report (/app/node_modules/@parcel/reporter-dev-server/lib/ServerReporter.js:67:31)
    at async ReporterRunner.report (/app/node_modules/@parcel/core/lib/ReporterRunner.js:105:11)

💁 Possible Solution

Couldn't find a workaround unfortunately, tried all sorts of combinations.

🔦 Context

Trying to use parcel in a module (ES6)-based project.

🌍 Your Environment

Software	Version(s)
Parcel	2.0.1
Node	v16.13.0
npm/Yarn	8.1.0
Operating System	Linux 4.18.0-348.el8.x86_64 x86_64 x86_64 x86_64 GNU/Linux

[mischnic]

The relevant code:

Search paths for the proxy config

parcel/packages/reporters/dev-server/src/Server.js

Lines 368 to 373 in 3eb0fc7

	const pkg = await loadConfig(
	this.options.inputFS,
	fileInRoot,
	['.proxyrc.js', '.proxyrc', '.proxyrc.json'],
	this.options.projectRoot,
	);

Location where the config is then required. (So .mjs would certainly be broken at the moment even after adding it to the list)

parcel/packages/core/utils/src/config.js

Lines 72 to 76 in 3eb0fc7

	let extname = path.extname(configFile).slice(1);
	if (extname === 'js') {
	let output = {
	// $FlowFixMe
	config: clone(require(configFile)),

[jaredatron]

Any update on when this might be fixed?

[Kali95739]

Yea we need a fix when you can

[jaredatron]

please add support for .proxyrc.cjs and .proxyrc.mjs

[jaredatron]

I temporary hacked around this problem by wrapping my parcel commands in a script that dynamically writes a .proxyrc file before calling parcel.