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A story captures the rendered state of a UI component. Given a set of arguments, it can be a simple object with annotations or a component that describes its behavior and appearance.
A story captures the rendered state of a UI component. It's an object with annotations that describe the component's behavior and appearance given a set of arguments.
Storybook uses the generic term arguments (args for short) when talking about React’s props, Vue’s props, Angular’s @Input, and other similar concepts.
A component’s stories are defined in a story file that lives alongside the component file. The story file is for development-only, and it won't be included in your production bundle. In your filesystem, it looks something like this:
components/
├─ Button/
│ ├─ Button.js | ts | jsx | tsx | vue | svelte
│ ├─ Button.stories.js | ts | jsx | tsx | svelte
We can define stories according to the Component Story Format (CSF), an ES6 module-based standard that is easy to write and portable between tools, or rely on the community-led project Svelte CSF which provides a similar experience.
With Svelte CSF, the essential elements are the defineMeta function, which describes the component, and the Story component, which describes the stories. This pattern is different from the standard CSF, which uses a default export and named exports to apply the same concepts.
We define stories according to the Component Story Format (CSF), an ES6 module-based standard that is easy to write and portable between tools.
The key ingredients are the default export that describes the component, and named exports that describe the stories.
The defineMeta function in Svelte CSF with native templating syntax controls how Storybook lists your stories and provides information used by addons. However, if you're not using this story format and relying on standard CSF, use the default export to achieve the same result. Below is an example of a story file with both approaches:
{/* prettier-ignore-start */}
{/* prettier-ignore-end */}
The default export metadata controls how Storybook lists your stories and provides information used by addons. For example, here’s the default export for a story file Button.stories.js|ts:
{/* prettier-ignore-start */}
{/* prettier-ignore-end */}
Starting with Storybook version 7.0, story titles are analyzed statically as part of the build process. The *default* export must contain a `title` property that can be read statically or a `component` property from which an automatic title can be computed. Using the `id` property to customize your story URL must also be statically readable.
If you're using Svelte CSF, define your stories with the Story component, otherwise use the named exports of a standard CSF file. We recommend you use UpperCamelCase for your story exports. Here’s how to render Button in the “primary” state and export a story called Primary using both methods.
Use the named exports of a CSF file to define your component’s stories. We recommend you use UpperCamelCase for your story exports. Here’s how to render Button in the “primary” state and export a story called Primary.
{/* prettier-ignore-start */}
{/* prettier-ignore-end */}
Unlike regular CSF, when using Svelte CSF, you cannot use args for children. Instead, you pass children in-between the opening and closing Story tags and it will be passed to the component as the children snippet prop.
<script module>
import { defineMeta } from '@storybook/addon-svelte-csf';
import Alert from './Alert.svelte';
const { Story } = defineMeta({
component: Alert,
});
</script>
{/* Renders <Alert>Alert text</Alert> */}
<Story name="Alert with children">
Alert text
</Story>If you want to render the children as the entire story itself, you can use the asChild prop of the Story component, which will ignore the default component rendering and render the children directly.
<Story
name="Default Button in alert"
asChild
/>
<Alert>
Alert text
<Button />
</Alert>
</Story>Note that features which require args, like Controls, will not work when using asChild. You can customize the rendering of a story and retain the ability to use args by using a custom render function.
By default, stories will render the component defined in the defineMeta call (for Svelte CSF) or in the default export (for CSF), with the args passed to it.
If you need to customize the rendering of your story, you can provide a snippet (for Svelte CSF) or a render fuction (for CSF) that accepts args and renders whatever you need.
For example, if you want to render a Button inside an Alert:
<Story
name="Primary in alert"
args={{
label: 'Button',
primary: true,
}}>
{#snippet template(args)}
<Alert>
Alert text
<Button {...args} />
</Alert>
{/snippet}
</Story>Note how the template snippet or render function spreads args onto the Button component. This ensures that features like Controls will work as expected, allowing you to dynamically change the Button's properties in the Storybook UI.
You can re-use the same render function across stories by applying it at the meta level. For Svelte CSF, this can be done by defining the template snippet outside of the story and assigning it to the render property of the defineMeta function. For CSF, you can define a render function in the default export.
<script module>
import { defineMeta } from '@storybook/addon-svelte-csf';
import Button from './Button.svelte';
const { Story } = defineMeta({
component: Button,
render: template,
});
</script>
{#snippet template(args)}
<Alert>
Alert text
<Button {...args} />
</Alert>
{/snippet}
<Story name="Default in alert" args={{ label: 'Button' }} />
<Story name="Primary in alert" args={{ label: 'Button', primary: true }} />Whatever you define at the meta level can be overridden at the story level, so you can still customize the rendering of individual stories if needed.
Finally, render functions and template snippets receive a second context argument, which contains all other details for the story, including parameters, globals, and more.
By default, stories will render the component defined in the meta (default export), with the args passed to it. If you need to render something else, you can provide a function to the render property that returns the desired output.
For example, if you want to render a Button inside an Alert, you can define a custom render function like this:
Note how the render function spreads args onto the Button component. This ensures that features like Controls will work as expected, allowing you to dynamically change the Button's properties in the Storybook UI.
You can re-use the same render function across stories by applying it at the meta level:
Whatever you define at the meta level can be overridden at the story level, so you can still customize the rendering of individual stories if needed.
Finally, render functions receive a second context argument, which contains all other details for the story, including parameters, globals, and more.
React Hooks are convenient helper methods to create components using a more streamlined approach. You can use them while creating your component's stories if you need them, although you should treat them as an advanced use case. We recommend args as much as possible when writing your own stories. As an example, here’s a story that uses React Hooks to change the button's state:
{/* prettier-ignore-start */}
{/* prettier-ignore-end */}
#### Working with Solid SignalsSolid Signals are convenient helper methods to create components using a more streamlined approach. You can use them while creating your component's stories if you need them, although you should treat them as an advanced use case. We recommend args as much as possible when writing your own stories. As an example, here’s a story that uses Solid Signals to change the button's state:
{/* prettier-ignore-start */}
{/* prettier-ignore-end */}
By default, Storybook uses the name of the story export as the basis for the story name. However, you can customize the name of your story by adding a name property to the story object. This is useful when you want to provide a more descriptive or user-friendly name for your story.
If you're using Svelte CSF, the name property is usually fairly descriptive and user-friendly already, so there is little need for renaming. However, the name is used as the basis for the export name, which must be unique within a file. In rare cases, this can lead to naming conflicts. For example, stories with the names "Primary" and "Primary!" would both be transformed to the "Primary" export name. To avoid this, you can use the exportName property to specify a unique export name for your story. exportName is also helpful to provide a more useful named export when re-using stories, e.g. as portable stories.
{/* prettier-ignore-start */}
{/* prettier-ignore-end */}
Your story will now be shown in the sidebar with the given text.
{/* Maintaining a prior heading */}
With Svelte, stories can be defined as objects using standard CSF or with Svelte CSF's Story component. Both methods describe how to render a component. You can have multiple stories per component, and those stories can build upon one another. For example, we can add Secondary and Tertiary stories based on our Primary story above.
A story is an object that describes how to render a component. You can have multiple stories per component, and those stories can build upon one another. For example, we can add Secondary and Tertiary stories based on our Primary story from above.
{/* prettier-ignore-start */}
{/* prettier-ignore-end */}
What’s more, you can import args to reuse when writing stories for other components, and it's helpful when you’re building composite components. For example, if we make a ButtonGroup story, we might remix two stories from its child component Button.
{/* prettier-ignore-start */}
{/* prettier-ignore-end */}
When Button’s signature changes, you only need to change Button’s stories to reflect the new schema, and ButtonGroup’s stories will automatically be updated. This pattern allows you to reuse your data definitions across the component hierarchy, making your stories more maintainable.
That’s not all! Each of the args from the story function are live editable using Storybook’s Controls panel. It means your team can dynamically change components in Storybook to stress test and find edge cases.