What version of Hugo are you using (hugo version)?

$ hugo version
Hugo Static Site Generator v0.70.0-7F47B99E linux/amd64 BuildDate: 2020-05-06T11:18:50Z

Does this issue reproduce with the latest release?

Yes

https://github.com/MarlonLuan/hugo-babel branch master contains code working

https://github.com/MarlonLuan/hugo-babel/tree/bug-babel-0.70 has code not work,

hugo server --source  site

Error: Error building site: BABEL: failed to transform "scripts/main.js" (application/javascript)