Using async code causes build to fail with "Module not found: Can't resolve '@babel/runtime/regenerator'"

[scpmx]

Is this a bug report?

Yes.

Environment

1. node -v: v16.6.1
2. npm -v: 7.20.5
3. yarn --version (if you use Yarn): N/A
4. npm ls create-elm-app -g: [email protected]

Then, specify:

1. Operating system: Mac OS
2. Browser and version (if relevant): Any

Steps to Reproduce

1. create-elm-app repro-steps
2. cd repro-steps
3. Add some async code to the bottom of src/index.js, such as:

async function foo() {
  var s = await bar();
  console.log(s);
}

function bar() {
  return "bar";
}

Expected Behavior

elm-app start and elm-app build run as expected

Actual Behavior

Both commands fail with the following error:

Failed to compile.

./src/index.js
Module not found: Can't resolve '@babel/runtime/regenerator' in '/Users/me/Projects/repro-steps/src'

[atlewee]

Observation: If you add a package.json with browserslist in it the error seems to go away... ? ... "author": "", "license": "ISC", "dependencies": {...}, "browserslist": [ "last 2 Chrome versions", "last 2 Edge versions", "Firefox ESR", "last 2 Safari versions", "last 2 iOS versions" ] ...