Remove core-js dependency from @babel/register

[coreyfarrell]

Q	A
Fixed Issues?
Patch: Bug Fix?	👍
Major: Breaking Change?
Minor: New Feature?
Tests Added + Pass?	Existing tests pass
Documentation PR Link
Any Dependency Changes?	👍
License	MIT

The dependency core-js is not actually used by @babel/register so this PR removes it.

[babel-bot]

Build successful! You can test your changes in the REPL here: https://babeljs.io/repl/build/10681/

[nicolo-ribaudo]

While this could be removed, I am a bit worried that it will break users using @babel/register @babel/preset-env with corejs: 3 without explicitly listing it in their dependencies.

cc @babel/babel

[ljharb]

anyone relying on this being implicitly present already has a bug; this error will surface their broken package.json most efficiently, at build time.

[suchipi]

Perhaps we should move the core-js dep to preset-env, then?

[chicoxyzzy]

LGTM

[nicolo-ribaudo]

Perhaps we should move the core-js dep to preset-env, then?

preset-env doesn't rely on core-js. Only it's output, when explicitly enabled by the user, does.
Also, we would need somehow to add both core-js 2 and 3 without aliasing them so it's not possible.

this error will surface their broken package.json most efficiently, at build time

Actually, @babel/runtime is executed at runtime by definition 😛
And also if it wasn't, the error would be a MODULE_NOT_FOUND thrown at runtime because of the injected core-js imports.

[ljharb]

ok, fair point on that. still tho, theoretically any test of any kind on a babelified file would expose it?