prefer babelrc defined node version target over pkg json engines field when --target node

[jthegedus]

🙋 feature request

When using --target node still prefer reading the node target from .babelrc if present.

🤔 Expected Behavior

if a .babelrc file is present and I use --target node I would like my explicit babel preset-env node version to be the target.

😯 Current Behavior

Currently, if --target node is found then the engines field is automatically used regardless of .babelrc
the parceljs code

💁 Possible Solution

when --target node prefer .babelrc over node engines field value.

🔦 Context

Firebase uses the engines field to specify the runtime for their Cloud Functions. They only support two specific numbers here, no semver ranges. Just

"engines": "6"
"engines": "8"

This causes issues when I want to dev in Node 10 with Yarn because the engines field does is not using a range, so I get an incompat node version error.

If it is omitted, then Node 6 is targetted, which would be fine, except that Parcel defaults to Node 8.

I asked to add range support to firebase which would solve the issue, but it does not seem like they will be addressing this on their end anytime soon.

If I could tell Parcel to target Node 6 via .babelrc then I could leave off the engines field and Firebase would target Node 6 and I could dev with Node 10 LTS & Yarn

I'm unsure what implications this could have on existing projects.

💻 Examples