[RFC] Rename storybook-addon-pseudo-states to @storybook/addon-pseudo-states

[alvis]

Summary

This RFC proposes renaming the npm package storybook-addon-pseudo-states to @storybook/addon-pseudo-states. The addon was absorbed into the Storybook organization, and renaming it to use the @storybook/ scope will make it consistent with all other first-party Storybook addons (e.g., @storybook/addon-essentials, @storybook/addon-interactions, etc.).

Problem Statement

The storybook-addon-pseudo-states addon was originally a community-created package. It has since been absorbed by the Storybook organization and is now maintained under the storybookjs GitHub org. However, its npm package name still uses the old unscoped storybook-addon-pseudo-states name rather than the @storybook/ scope used by all official Storybook packages. This inconsistency creates confusion for users who expect official Storybook addons to be published under the @storybook/ npm scope.

Non-goals

• This RFC does not propose any changes to the addon's functionality, API, or behavior — it is purely a rename/republish.
• This RFC does not cover migrating the repository itself (it already lives in storybookjs/storybook-addon-pseudo-states or the monorepo).
• This RFC does not cover deprecating or removing existing functionality.

Implementation

1. Publish @storybook/addon-pseudo-states on npm — Publish the package under the new scoped name @storybook/addon-pseudo-states. The package contents (source code, exports, peer dependencies) remain identical.

2. Deprecate the old package — Mark storybook-addon-pseudo-states as deprecated on npm with a message pointing users to @storybook/addon-pseudo-states. The old package should re-export from the new package for a transitional period to avoid breaking existing users.

3. Update documentation — Update all references in the official Storybook docs, README, and integration guides from storybook-addon-pseudo-states to @storybook/addon-pseudo-states.

4. Update internal references — Update any references within the Storybook monorepo, CI configs, and related tooling.

5. Migration guide — Provide a short migration guide so existing users know to update their package.json and (if applicable) .storybook/main.js addon registration from storybook-addon-pseudo-states to @storybook/addon-pseudo-states.

Prior Art

This pattern has been followed before within the Storybook ecosystem. Several addons that were originally community packages have been absorbed and republished under the @storybook/ scope, such as @storybook/addon-interactions (formerly community-maintained) and @storybook/addon-a11y. The npm deprecation + re-export pattern is a well-established approach for package renames in the JavaScript ecosystem.

Deliverables

1. Publish @storybook/addon-pseudo-states on npm with the existing source code
2. Deprecate storybook-addon-pseudo-states on npm with a redirect message and add a re-export shim for backwards compatibility
3. Update Storybook documentation and README to reference the new package name
4. Publish migration guide and announce the rename to users via release notes / changelog

Risks

• Breaking change for existing users: Users who do not update their package.json will continue to use the old deprecated package. Mitigation: keep the old package published (but deprecated) and add a re-export shim so it continues to work for at least one major version cycle.
• SEO / discoverability confusion: Both package names may appear in search results for a period. Mitigation: clear deprecation notice on the old npm package pointing to the new name.
• CI/CD pipeline references: Any internal or community tooling that references the old package name by string will need updating. Mitigation: document all known references in the migration guide.

Unresolved Questions

• Should the old storybook-addon-pseudo-states package be kept as a re-export shim for one major version, or for a fixed time period (e.g., 6 months)?
• Is there any tooling (e.g., storybook automigrate) that should be updated to handle this rename automatically for users?

Alternatives considered / Abandoned Ideas

No response