ReferenceError: regeneratorRuntime babel-present-env error?

I think this may be a bug with babel-preset-env, just checking here first. I’m getting the error below when trying to run the tests for a new exercise I’m implementing. This error refers to this line: function* generate(A) {. Generator functions are part of the babel-preset-es2015 which should be included in babel-preset-env so I’m not sure why this is happening. Any ideas? Thanks!

 ● Test suite failed to run

    ReferenceError: regeneratorRuntime is not defined

      at Object.<anonymous> (exercises/alphametics/tmp/alphametics.js:57:15)
      at Object.<anonymous> (exercises/alphametics/tmp/temp.alphametics.spec.js:1:122)

Test Suites: 1 failed, 1 total

[arthurchipdean]

@rchavarria You are right, after adding the babel-polyfil the error has gone away. Thanks for your help!

[rchavarria]

I have no idea about how to configure Babel nowadays (I did it in the past, but it has evolved a lot since then).

But just looking at the documentation, if I compare the support for arrow functions (a basic feature that makes sense to be included by default) to generators (a not so basic feature) I notice a difference:

The generators documentation shows a warning:

Runtime required You need to use either the Babel polyfill or the regenerator runtime so that regeneratorRuntime will be defined.

It seems if we want to use generators we need a plugin.