Why does Babel throw Unknown option: ... Children? - babeljs

Question

Trying to run build on CircleCi and it's failing on test. Same stuff is working perfect on my local.
My .babelrc config:
{
"presets": [
"es2015",
"react",
"stage-2"
],
"plugins": [
"transform-class-properties",
"react-hot-loader/babel",
["babel-plugin-transform-builtin-extend", {
"globals": ["Error", "Array"]
}],
["transform-runtime", {
"polyfill": false,
"regenerator": true
}]
]
}
Error I'm getting from circleCI:
yarn test v0.27.5
$ jest
FAIL src/utils/service-helper.test.js
● Test suite failed to run
ReferenceError: [BABEL] /home/circleci/repo/src/utils/service-helper.test.js: Unknown option: /home/circleci/repo/node_modules/react/index.js.Children. Check out http://babeljs.io/docs/usage/options/ for more information about options.
A common cause of this error is the presence of a configuration options object without the corresponding preset name. Example:
Invalid:
`{ presets: [{option: value}] }`
Valid:
`{ presets: [['presetName', {option: value}]] }`
Any idea what is going on as the same configuration is working on another project

Answer 1

The error is unhelpful, but the issue is that your config has react in the preset list, but it can't find the babel-preset-react module in your node_modules, so instead it is loading the react module itself as if it were a preset. But since the "react" module isn't a preset, Babel throws.
Most likely, you've forgotten to list babel-preset-react in your package.json.