for...of inside generator function causes transpilation failure

[conartist6]

preset-react-app has the issue described here: https://github.com/leebenson/babel-preset-node5/issues/4

Is this a bug report?

Yes

Steps to Reproduce

set a browserslist in package.json which which includes only browsers which support for...of loops, e.g.

  "browserslist": {
    "production": ["last 1 chrome versions"]
  },

Attempt to build an application which contains a for...of loop inside a generator function, like so:

function* willFailCompilation(array) {
  for (const item of array) {
      yield item;
  }
}

Expected Behavior

The app does not fail compilation

Actual Behavior

This error is shown:
Failed to compile

Module build failed: Error: unknown Statement of type "ForOfStatement"
at Array.forEach ()

Reproducible Demo

[none]

[conartist6]

Directly including regenerator in preset-react-app's plugins list predates the existence of preset-env.

Preset-env will transpile generators if browserslist requires it.

Therefore I think the correct solution is simply to remove transform-regenerator here. However I am having a truly awful time trying to verify it, or even reliably reproduce the problem I was having in the first place.

[conartist6]

OK I have been able to verify locally that removing regenerator does not eliminate transpilation of generator functions when preset-env dictates that they need to be transpiled.