Polish @babel/node REPL

[JLHwung]

Q	A
Fixed Issues?	Fixes #10739
Tests Added + Pass?	Yes
Documentation PR Link
Any Dependency Changes?
License	MIT

This PR polishes the @babel/node REPL.

• Toggled on preview: true REPL options: it will output the preview (like Chrome DevTools did) of evaluation result on supported node.js version (v13.4.0, v12.17.0)
• setup history from process.env.NODE_REPL_HISOTRY, if it is not given, Node.js will default to ~/.node_repl_history (v11.10.0). Although we could implement REPL history support for lower versions, I don't think it is worthy since Babel 8 will drop Node < 12 support. Thanks for @0xdevalias offering a detailed report (babel-node should support NODE_REPL_HISTORY #10739) on this feature!

I marked this PR as Polish because there is no new options/methods added.

[babel-bot]

Build successful! You can test your changes in the REPL here: https://babeljs.io/repl/build/40085/

[nicolo-ribaudo]

Love when improvements are just a few lines of code 😂

[codesandbox-ci]

This pull request is automatically built and testable in CodeSandbox.

To see build info of the built libraries, click here or the icon next to each commit SHA.

Latest deployment of this branch, based on commit db1be54:

Sandbox	Source
babel-repl-custom-plugin	Configuration
babel-plugin-multi-config	Configuration

[hzoo]

wow nice!

my q with creating files is wondering how big they get without clearing (reminded of babel register cache, tho I'm sure this is much smaller)

[JLHwung]

@hzoo The ~/.node_repl_history is not created by Babel, it is created when you run a Node.js REPL or in this case we set up a REPL server if you have never run node REPL before. The change in this PR instruct node to reuse current ~/.node_repl_history. By default Node.js will clear REPL history when it is more than 1000 lines: https://nodejs.org/api/repl.html#repl_environment_variable_options

Note that if users do not want @babel/node reusing Node.js REPL history, they should provide their own REPL_HISTORY

NODE_REPL_HISTORY=~/.babel_node_repl_history babel-node

[nicolo-ribaudo]

Does this need to wait for a minor version?

[JLHwung]

@nicolo-ribaudo I think it can be shipped in patch.