When an arg’s value is changed, the component re-renders, allowing you to interact with components in Storybook’s UI via addons that affect args.
Learn how and why to write stories in the introduction. For details on how args work, read on.
The args object can be defined at the story and component level (see below). It is an object with string keys, where values can have any type that is allowed to be passed into a component in your framework.
To define the args of a single story, use the
args CSF story key:
In the above example, we use the object spread feature of ES 2015.
You can also define args at the component level; such args will apply to all stories of the component unless they are overwritten. To do so, use the
args key of the
default CSF export:
You can separate the arguments to a story to compose in other stories. Here’s how args can be used in multiple stories for the same component.
Note that if you are doing the above often, you may want to consider using component-level args.
Args are useful when writing stories for composite components that are assembled from other components. Composite components often pass their arguments unchanged to their child components, and similarly their stories can be compositions of their child components stories. With args, you can directly compose the arguments:
Args are used in story templates to configure the component appearance just as you would in an application. Here’s an example of how a
footer arg can be used to populate a child component.
Initial args for the currently active story can be overruled by setting the
args query parameter on the URL. Typically, you would use the Controls addon to handle this automatically, but you can also manually tweak the URL if desired. An example of Storybook URL query params could look like this:
In order to protect against XSS attacks, keys and values of args specified through the URL are limited to alphanumeric characters, spaces, underscores and dashes. Any args that don't abide these restrictions will be ignored and stripped, but can still be used through code and manipulated through the Controls addon.
args param is always a set of
key:value pairs delimited with a semicolon
;. Values will be coerced (cast) to their respective
argTypes (which may have been automatically inferred). Objects and arrays are supported. Special values
undefined can be set by prefixing with a bang
!. For example,
args=obj.key:val;arr:one;arr:two;nil:!null will be interpreted as:
Similarly, special formats are available for dates and colors. Date objects will be encoded as
!date(value) with value represented as an ISO date string. Colors are encoded as
!hsla(value). Note that rgb(a) and hsl(a) should not contain spaces or percentage signs in the URL.
Args specified through the URL will extend and override any default values of args specified on the story.
Complex values such as JSX elements cannot be serialized to the manager (e.g. the Controls addon) or synced with the URL. To work around this limitation, arg values can be "mapped" from a simple string to a complex type using the
mapping property in
argTypes. This works on any type of arg, but makes most sense when used with the
select control type.
mapping does not have to be exhaustive. If the arg value is not a property of
mapping, the value will be used directly. Keys in
mapping always correspond to arg values, not their index in the
If you are writing an addon that wants to read or update args, use the
useArgs hook exported by
In Storybook 6+, we pass the args as the first argument to the story function. The second argument is the “context” which contains things like the story parameters etc.
In Storybook 5 and before we passed the context as the first argument. If you’d like to revert to that functionality set the
parameters.passArgsFirst parameter in
args is still available as a key on the context.