---
title: 'Frequently Asked Questions'
---

Here are some answers to frequently asked questions. If you have a question, you can ask it by opening an issue on the [Storybook Repository](https://github.com/storybookjs/storybook/).

### How can I run coverage tests with Create React App and leave out stories?

Create React App does not allow providing options to Jest in your `package.json`, however you can run `jest` with commandline arguments:

```sh
npm test -- --coverage --collectCoverageFrom='["src/**/*.{js,jsx}","!src/**/stories/*"]'
```

### I see `ReferenceError: React is not defined` when using storybooks with Next.js

Next automatically defines `React` for all of your files via a babel plugin. You must define `React` for JSX to work. You can solve this either by:

1.  Adding `import React from 'react'` to your component files.
2.  Adding a `.babelrc` that includes [`babel-plugin-react-require`](https://www.npmjs.com/package/babel-plugin-react-require)

### How do I setup Storybook to share Webpack configuration with Next.js?

You can generally reuse webpack rules by placing them in a file that is `require()`-ed from both your `next.config.js` and your `.storybook/main.js` files. For example:

```js
module.exports = {
  webpackFinal: async (baseConfig) => {
    const nextConfig = require('/path/to/next.config.js');

    // merge whatever from nextConfig into the webpack config storybook will use
    return { ...baseConfig };
  },
};
```

### Why is there no addons channel?

A common error is that an addon tries to access the "channel", but the channel is not set. This can happen in a few different cases:

1.  You're trying to access addon channel (e.g. by calling `setOptions`) in a non-browser environment like Jest. You may need to add a channel mock:
    ```js
    import addons, { mockChannel } from '@storybook/addons';

    addons.setChannel(mockChannel());
    ```

2.  In React Native, it's a special case that's documented in [#1192](https://github.com/storybookjs/storybook/issues/1192)

### Can I modify React component state in stories?

Not directly. If you control the component source, you can do something like this:

```js
import React, { Component } from 'react';

export default {
  title: 'MyComponent',
};

class MyComponent extends Component {
  constructor(props) {
    super(props);

    this.state = {
      someVar: 'defaultValue',
      ...props.initialState,
    };
  }
  // ...
};

export const defaultView = () => <MyComponent initialState={} />;
```