Simplify the printing logic for ( before ambiguous tokens

[nicolo-ribaudo]

Q	A
Fixed Issues?	Fixes #1, Fixes #2
Patch: Bug Fix?
Major: Breaking Change?
Minor: New Feature?
Tests Added + Pass?	Yes
Documentation PR Link
Any Dependency Changes?
License	MIT

See #16648. With this change we don't need to manually list cases where ( is needed anymore, and we do not need to walk up in the tree.

[babel-bot]

Build successful! You can test your changes in the REPL here: https://babeljs.io/repl/build/57371

[liuxingbaoyu]

Amazing!
I ran a benchmark and in Babel 7 it's just as fast as before.
And in Babel 8 we can enable babelPluginInlineConstNumericObjects for generator to make it even faster!

[kungfooman]

This looks like the case for:

const ast = Babel.packages.parser.parse("type x = ?    number; /**/", {plugins: ['flow']});
Babel.packages.generator.default(ast);
// Outputs: {code: 'type x = ?number; /**/', decodedMap: undefined}

(but I can't test it easily through debugging or stepping into the code, since the repl build is helplessly minified - would be nice if a PR preview was readable/debuggable)

[liuxingbaoyu]

https://astexplorer.net/#/gist/65e561e94ad90a154646cfd21be92f52/26ebbf2128f469b1469f574a3fb76b167b53f8e2
You can use it.
Also I remember that the repl has source maps, so debugging should be possible. :)

[kungfooman]

@liuxingbaoyu Thank you! Good point, it works very nicely. Somehow I went through babeljs.io in source tab and not output.circle-artifacts.com... now that I could set a breakpoint I realized my code snippet wasn't for that case (so the comment may be correct lol).

Only strange thing is it's called optional in different places too, even though it's just nullable (optional in JS means some type or undefined).

[nicolo-ribaudo]

Thanks for the investigation, I'll re-check and see what we need to do here :)