using: Allow looking up Symbol.dispose on a function

[odinho]

This works with browsers and it allows the nice pattern of returning a function that allows you to do something directly with what you used.

I'm just using this to do early 'unpause'-ing of undo functionality.

{
  using unpause = pauseUndo();
  code.doThings();
  if (weAreSomehowDone) unpause();
  code.doOtherThing();
}

It doesn't seem so restrictive in the spec, as a function is also an object, but it has a different typeof name.

[babel-bot]

Build successful! You can test your changes in the REPL here: https://babeljs.io/repl/build/55958/

[nicolo-ribaudo]

Thank you! Yes, this is a bug in our implementation.

I left a minor comment just to make the code slightly smaller. Then, could you:

1. run make build to re-generate the babel-helpers/src/helpers-generated.ts file
2. Add a test in packages/babel-plugin-proposal-explicit-resource-management/test/fixtures (look for folders containing exec.js there, and create a new one similar to those)

[odinho]

@nicolo-ribaudo: Thank you for the very quick review!

I've tried doing what you said ^_^

Added two tests sync/async with slight variations (one wrapped in a call, one just given to using directly).

[liuxingbaoyu]

Thanks!

[nicolo-ribaudo]

Thank you!