Error: Plugin/Preset files are not allowed to export objects, only functions.

Bug Report

Environment

"babel": "^6.23.0",
"babel-cli": "^6.26.0",
"babel-core": "^6.26.3"

OSX: 10.13.6 (17G3014)

node -v
v10.0.0

npm -v
5.6.0

Babel Configuration (.babelrc)

{
  "presets": [ "react",  ["env", {
    "targets": {
     "browsers": [ ">0.25%", "not ie 11", "not op_mini all"]
    }
  }], "stage-0" ],
  "env": {
   "production": {
      "presets": ["minify"]
    }
  },
  "plugins": [
    [ "transform-object-rest-spread", { "useBuiltIns": true } ],
    "transform-es2015-destructuring",
    "transform-runtime",
    "transform-decorators-legacy",
    "transform-class-properties"
  ]
}

Want to transform code

import { transform } from '@babel/core'
...
const source = await readFile(fileName)
const posixName = posixPath(fileName)
const result = transform(source, {
  babelrc: true,
  filename: fileName
})

Current Behavior

Error: Plugin/Preset files are not allowed to export objects, only functions.

Expected behavior/code Code is successfully transformed regarded to working project with that babel config.

[nicolo-ribaudo]

Error: Cannot find module ‘babel/core’

It’s babel-core, not babel/core

Probably some of your dependencies depends on @babel/core, so you are able to import it because it is hoisted by npm.

[loganfsmyth]

Also, FYI we have a transformFile function, so you don’t need to read the file yourself, and converting with posixPath shouldn’t be needed.