Storybook is a powerful tool which can be integrated into any React, Angular, or Vue application or standalone component library. As well as being a catalogue of components, it provides a sandbox to allow components to be developed and tested in isolation across the entire range of use cases (or "stories", in Storybook parlance) which those components support. Alongside those stories, Storybook displays documentation about each component in a way that makes it easy to see and understand what a component does. This documentation is generated automatically using metadata within each component, which removes the need to maintain a separate repository of documentation. The composition of the documentation is highly flexible, and further customisation options are available to allow more advanced control over the presentation of the documentation if it is needed.
In the last major release, a new feature called Controls was added which enables a user to interact with a component by changing the data being passed into it using some interactive controls generated automatically by Storybook. This is very powerful, as it allows users (including those without a technical background) to experiment with the appearance and behaviour of a component in isolation before it is integrated into an application.
Another feature of Storybook is support for unit tests, which can be written to ensure that the component works as expected for each of the stories it supports. Traditionally, this would be harder to do if the component was being developed directly into the page of an application. In addition to unit testing, Storybook provides tools to support visual testing (has the component changed visually?), snapshot testing (has the markup generated by the component changed?) and interaction testing (does the component respond as expected in response to user interaction?). Storybook offers several options around testing of components, all of which help to improve test coverage and ensure that components are stable, robust, and function as intended.
By having a platform which documents components, what they look like, and how they function, Storybook provides the basis of a design system, which are becoming more popular in modern organisations. Design systems are typically used by developers and designers, and they help to define a single source of truth about what front-end components are available in an organisation, and what brand identity and design patterns should be followed when using those components. They provide clear guidance to developers and designers about how to use those components in a manner consistent with the message that the organisation aims to project to the outside world. Many organisations, particularly those whose components are used by developers outside of their organisation, have published their design systems - Atlassian, Microsoft, and Shopify are great examples of these. Storybook helps to promote design systems and even provides a specific tutorial about how to build design systems with Storybook.
There is much more to discover about Storybook than the topics covered in this post, but this post should give a taster of the basic ethos that Storybook tries to promote - to help developers lay the foundations for modern, modular, and maintainable component libraries. In my next blog post, we'll build a simple React component and integrate it with Storybook, in order to see what that component looks like in Storybook and explore some of the features described in this post.