added support Node's --require and -r flags in babel-node

[stuneak]

Q	A
Fixed Issues?	#7465
Patch: Bug Fix?	n
Major: Breaking Change?	n
Minor: New Feature?	y
Tests Added + Pass?	n
Documentation PR
Any Dependency Changes?	n
License	MIT

[babel-bot]

Build successful! You can test your changes in the REPL here: https://babeljs.io/repl/build/7238/

[danez]

--require has an option according to the docu: https://nodejs.org/api/cli.html#cli_r_require_module
So using flag here is probably wrong and should be arg instead, but I haven't tested it, so correct me if I'm wrong.

[danez]

Although it seems I missed that the module is not separated by equal sign but with space in this case, so flag and arg are the same. Still I think this will not work as the preceding module name will be pushed to args (in the switch-default) whereas this here gets unshifted.

[mkovel]

Hi guys, can you push forward a little with this task? I am very looking forward it.
Thanks.

[danez]

Okay I checked it and it wasn't working. I pushed a commit now it is working

[mkovel]

Guys, when do you plan, include this awesome feature in a release?

[jdalton]

Hi all!

Thanks for adding this feature! At the moment though it looks like the -r option doesn't resolve modules like the traditional node -r by that I mean babel-node -r esm will result in an error

Cannot find module '/Users/jdalton/projects/bar/esm'

because it's not resolving esm to the node_modules folder of

'/Users/jdalton/projects/bar/node_modules/esm'

[danez]

I see so we should change this line https://github.com/babel/babel/pull/7471/files#diff-bd092c1aa1f13cc3b620707dc4fc8a1eR153 to check if the path starts with dot and only then append cwd. In the other cases (absolute paths starting with / or modules starting with [a-zA-Z]) we can simply require them.

Not sure about Windows though.

[jdalton]

@danez Node has an API, require.resolve(path, { paths:['.'] })], in Node 8+ that that uses Node's own path resolution to resolve path to the current working directly. This would handle resolving absolute, local, and package names. There may be a package on npm to backport the API for Node 6 (the actual bit of code internally is like 5 lines).

const Module = require('module')
const fakeParent = new Module('', null)

fakeParent.paths = Module._nodeModulePaths('.')
const paths = ['.', ...Module._resolveLookupPaths(request, fakeParent, true)]
const filename = Module._findPath(request, paths, false)

[loganfsmyth]

My vote would be to use resolve rather than rely on internals of Node, but otherwise sounds like a good plan.

[jdalton]

The idea wouldn't be to use Node internals for all-the-things. It would be to fork and only use the internals for Node < 8. Though an external package is cool too.