Invalid PostCSS Plugin found at: plugins[0]

v13 of this plugin won’t compile for me. Is there something different I need to do to import the plugin as of v13?

Failed to compile.

./src/assets/Index.css (./node_modules/css-loader/dist/cjs.js??ref--5-oneOf-4-1!./node_modules/react-scripts/node_modules/postcss-loader/src??postcss!./src/assets/Index.css)
TypeError: Invalid PostCSS Plugin found at: plugins[0]

(@/Users/dfalling/Code/ido/postcss.config.js)
    at Array.forEach (<anonymous>)

Node 10.18.0

postcss.config.js:

const postcssImport = require("postcss-import");

module.exports = {
  plugins: [
    postcssImport
  ],
};

package.json:

    "postcss": "8.1.4",
    "postcss-loader": "4.0.4",
    "postcss-import": "13.0.0",

[AlexVipond]

In case anyone else hits this error, I was getting it because I forgot to update my global postcss-cli installation to 8.x

Updating postcss-cli cleared everything up 👍

[RyanZim]

Found it! The error message indicates it’s coming from ./node_modules/react-scripts/node_modules/postcss-loader, which means your build process isn’t using the version of postcss-loader you have in your package.json, it’s using the postcss-loader that react-scripts pulls in, which happens to be postcss-loader@3.0.0: https://github.com/facebook/create-react-app/blob/aec42e2cc05fe0799a3b73830b874757e9e3f561/packages/react-scripts/package.json#L69

To use postcss v8 plugins, you’ll either have to stop using react-scripts, or wait for react-scripts to upgrade their version of postcss-loader to be compatible with postcss v8. Of course, you can also downgrade to postcss-import v12, which uses postcss v8.