Error: Node Sass version 5.0.0 is incompatible with ^4.0.0

Question

I've created a blank React project, using the command: npx create-react-app on npm v7.0.7 and Node v15.0.1

Installed:

• React v17.0.1,
• node-sass v5.0.0,

Then I tried to import blank .scss file to App component:

App.js

import './App.scss'

function App() {
  return (
    <div className="App">
      App
    </div>
  );
}

export default App;

Throw an Error:

Failed to compile.

./src/App.scss (./node_modules/css-loader/dist/cjs.js??ref--5-oneOf-6-1!./node_modules/postcss-loader/src??postcss!./node_modules/resolve-url-loader??ref--5-oneOf-6-3!./node_modules/s
ass-loader/dist/cjs.js??ref--5-oneOf-6-4!./src/App.scss)
Error: Node Sass version 5.0.0 is incompatible with ^4.0.0.

package.json

{
  "name": "react-17-node-sass-5",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "@testing-library/jest-dom": "^5.11.5",
    "@testing-library/react": "^11.1.0",
    "@testing-library/user-event": "^12.1.10",
    "node-sass": "^5.0.0",
    "react": "^17.0.1",
    "react-dom": "^17.0.1",
    "react-scripts": "4.0.0",
    "web-vitals": "^0.2.4"
  },
 ...
 
  }
}

Answer 1

TL;DR

1. npm uninstall node-sass
2. npm install [email protected]

Or, if using yarn (default in newer CRA versions)

1. yarn remove node-sass
2. yarn add [email protected]

---

Edit2: sass-loader v10.0.5 fixes it. Problem is, you might not be using it as a project dependency, but more as a dependency of your dependencies. CRA uses a fixed version, angular-cli locks to node-sass v4 an so on.
The recommendation for now is: if you're installing just node-sass check below workaround (and the note). If you're working on a blank project and you can manage your webpack configuration (not using CRA or a CLI to scaffold your project) install latest sass-loader.

---

Edit: this error comes from sass-loader. There is a semver mismatch since node-sass @latest is v5.0.0 and sass-loader expects ^4.0.0.
There is an open issue on their repository with an associated fix that needs to be reviewed. Until then, refer to the solution below.

---

Workaround: don't install node-sass 5.0.0 yet (major version was just bumped).

Uninstall node-sass

npm uninstall node-sass

Then install the latest version (before 5.0)

npm install [email protected]

---

Note: LibSass (hence node-sass as well) is deprecated and dart-sass is the recommended implementation. You can use sass instead, which is a node distribution of dart-sass compiled to pure JavaScript. Be warned though:

Be careful using this approach. React-scripts uses sass-loader v8, which prefers node-sass to sass (which has some syntax not supported by node-sass). If both are installed and the user worked with sass, this could lead to errors on css compilation