rsnext/errors/postcss-function.mdx

---
title: PostCSS Configuration Is a Function
---

## Why This Error Occurred

The project's custom PostCSS configuration exports a function instead of an object.

## Possible Ways to Fix It

Adjust the custom PostCSS configuration to not export a function. Instead, return a plain object.

If you need environment information, read it from `process.env`.

**Before**

```js filename="postcss.config.js"
module.exports = ({ env }) => ({
  plugins: {
    'postcss-plugin': env === 'production' ? {} : false,
  },
})
```

**After**

```js filename="postcss.config.js"
module.exports = {
  plugins: {
    'postcss-plugin': process.env.NODE_ENV === 'production' ? {} : false,
  },
}
```