> **Version 9** — **React** / **TypeScript**
> Also available:
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- `?language=js` for JavaScript
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- other versions: Version 10.3 (latest) (`/docs/essentials/actions.md`), Version 8 (`/docs/8/essentials/actions.md`)

# Actions

Actions are used to display data received by event handler (callback) arguments in your stories.

## Action args

Actions work via supplying special Storybook-generated “action” arguments (referred to as "args" for short) to your stories. There are two ways to get an action arg:

### Via storybook/test fn spy function

The recommended way to write actions is to use the `fn` utility from `storybook/test` to mock and spy args. This is very useful for writing [interaction tests](../writing-tests/interaction-testing.mdx). You can mock your component's methods by assigning them to the `fn()` function:

```ts
// Button.stories.ts|tsx
// Replace your-framework with the framework you are using, e.g. react-vite, nextjs, vue3-vite, etc.

const meta = {
  component: Button,
  // 👇 Use `fn` to spy on the onClick arg, which will appear in the actions panel once invoked
  args: { onClick: fn() },
} satisfies Meta<typeof Button>;

export default meta;
```

If your component calls an arg (because of either the user's interaction or the `play` function) and that arg is spied on , the event will show up in the action panel:

![Actions usage](../_assets/essentials/addon-actions-screenshot.png)

### Automatically matching args

Another option is to use a global parameter to match all [argTypes](../api/arg-types.mdx) that match a certain pattern. The following configuration automatically creates actions for each `on` argType (which you can either specify manually or can be [inferred automatically](../api/arg-types.mdx#automatic-argtype-inference)).

This is quite useful when your component has dozens (or hundreds) of methods and you do not want to manually apply the `fn` utility for each of those methods. However, **this is not the recommended** way of writing actions. That's because automatically inferred args **are not available as spies in your play function**. If you use `argTypesRegex` and your stories have play functions, you will need to also define args with the `fn` utility to test them in your play function.

```ts
// .storybook/preview.ts
// Replace your-framework with the framework you are using, e.g. react-vite, nextjs, vue3-vite, etc.

const preview: Preview = {
  parameters: {
    actions: { argTypesRegex: '^on.*' },
  },
};

export default preview;
```

If you need more granular control over which `argTypes` are matched, you can adjust your stories and include the `argTypesRegex` parameter. For example:

```ts
// Button.stories.ts|tsx
// Replace your-framework with the framework you are using, e.g. react-vite, nextjs, vue3-vite, etc.

const meta = {
  component: Button,
  parameters: { actions: { argTypesRegex: '^on.*' } },
} satisfies Meta<typeof Button>;

export default meta;
```

This will bind a standard HTML event handler to the outermost HTML element rendered by your component and trigger an action when the event is called for a given selector. The format is `<eventname> <selector>`. The selector is optional; it defaults to all elements.

## API

### Parameters

This contributes the following [parameters](../writing-stories/parameters.mdx) to Storybook, under the `actions` namespace:

#### `argTypesRegex`

Type: `string`

Create actions for each arg that matches the regex. Please note the significant [limitations of this approach](#automatically-matching-args), as described above.

#### `disable`

Type: `boolean`

Disable the action panel.

This parameter is most useful to allow overriding at more specific levels. For example, if this parameter is set to `true` at the project level, it could then be re-enabled by setting it to `false` at the meta (component) or story level.

### Exports

```js

```

#### `action`

Type: `(name?: string) => void`

Allows you to create an action that appears in the actions panel of the Storybook UI when clicked. The action function takes an optional name parameter, which is used to identify the action in the UI.

```ts
// Button.stories.ts
// Replace your-framework with the framework you are using, e.g. react-vite, nextjs, vue3-vite, etc.

const meta = {
  component: Button,
  args: {
    // 👇 Create an action that appears when the onClick event is fired
    onClick: action('on-click'),
  },
} satisfies Meta<typeof Button>;

export default meta;
```