Storybook 8.4 comes with a ton of exciting new features designed to give you the best experience developing, testing, and debugging tests in the browser!

▶️ Unified UI for component testing
5️⃣ Svelte 5 and Svelte CSF support
⚛️ React Native Storybook 8 release
🏷️ Tags-based filtering to organize your Storybook
🫧 Dependency cleanup to reduce install footprint
💯 Hundreds more improvements

<details> <summary>List of all updates</summary>

Addon Test: Adjust file exports to be ESM/CJS compatible - #29471, thanks @valentinpalkovic!
Addon Test: Error when addon interactions exists - #29434, thanks @valentinpalkovic!
Addon Test: Escape XML when converting ANSI to HTML in test errors - #29446, thanks @ghengeveld!
Addon Test: Fix hiding stacktrace for assertion errors in test panel - #29458, thanks @ghengeveld!
Addon Test: Improve Error Handling - #29476, thanks @valentinpalkovic!
Addon Test: Improve postinstall script - #29479, thanks @yannbf!
Addon Test: Improve unsupported vitest message - #29486, thanks @valentinpalkovic!
Addon Test: Only register testing module in Vite projects - #29472, thanks @yannbf!
Addon Test: Throttle Vitest progress updates more heavily - #29482, thanks @ghengeveld!
Addon-docs, blocks: Prebundle dependencies - #29301, thanks @JReinhold!
Addon-Test: Support for @vitest/browser v2.1.2 - #29407, thanks @strozw!
Blocks: Prebundle es-toolkit - #29259, thanks @JReinhold!
Builder-vite: Replace .at() call with [] in codegen - #29048, thanks @Chudesnov!
CLI: Don't add @storybook/addon-links by default - #29177, thanks @tobiasdiez!
CLI: Ensure .gitignore updated via CLI ends with a newline - #29124, thanks @3w36zj6!
CLI: Fix yarn detection - #29448, thanks @ndelangen!
CLI: Migrate from chalk to picocolors - #28262, thanks @43081j!
CLI: Refactor NPMProxy error parsing logic - #29459, thanks @yannbf!
ConfigFile: Fix export { X } parsing - #29344, thanks @vctqs1!
Core: Add unified UI Testing Module - #29241, thanks @yannbf!
Core: Close story status menu when selecting an item - #29455, thanks @ghengeveld!
Core: Fix building Storybook deleting project root files - #29371, thanks @JReinhold!
Core: Fix race condition during empty folder init - #29490, thanks @valentinpalkovic!
Core: Make prettier an optional peer dependency - #29223, thanks @JReinhold!
Core: Migrate from express to polka - #29230, thanks @43081j!
Core: Migrate from qs to picoquery - #28315, thanks @43081j!
Core: Open 'Component tests' addon panel when clicking a story status - #29456, thanks @ghengeveld!
Core: Remove handlebars usage - #29208, thanks @ndelangen!
Core: Remove dependence on file-system-cache - #29256, thanks @ndelangen!
Core: Replace fs-extra with the native APIs - #29126, thanks @ziebam!
Core: Replace lodash with es-toolkit - #28981, thanks @ndelangen!
Core: Show checkmark icon in story status dropdown and update status label for component tests - #29451, thanks @ghengeveld!
Core: Show tooltip on filter toggles to clarify their purpose - #29447, thanks @ghengeveld!
Core: Track test provider state in sessionStorage - #29450, thanks @ghengeveld!
Core: Upgrade esbuild, broadening version range - #29254, thanks @ndelangen!
Dependencies: Upgrade VTA to v3.1.0 - #29449, thanks @ghengeveld!
Dependencies: Upgrade VTA to v3.2.0 to resolve peerDep conflict - #29461, thanks @ghengeveld!
Interactions: Escape xml of interactions errors - #29414, thanks @kasperpeulen!
Maintenance: Fix broken and outdated documentation links - #29412, thanks @jonniebigodes!
Manager: Add tags property to ComponentEntry objects - #29343, thanks @Sidnioulz!
React: Prebundle all of renderers/react's dependencies - #29298, thanks @ndelangen!
Svelte: Improve argTypes inference with svelte2tsx - support runes - #29423, thanks @JReinhold!
Test: Remove unused util dependency - #29310, thanks @JReinhold!
UI: Brand image css class conflict causes image to resize on hot reloads - #29129, thanks @ShreySinha02!
UI: Fix RefIndicator to use CheckIcon instead of string - #29209, thanks @JSMike!
UI: Simple tag filtering - #29333, thanks @shilman!
UI: Use production-mode react in manager - #29197, thanks @ndelangen!
Viewport-addon: Add InitialViewportKeys type to viewport addon - #29182, thanks @hyeongrok7874!
Vite: Add jsdoc-type-pratt-parser to optimizeDeps - #29179, thanks @tobiasdiez!
Vite: Cleanup and prebundle dependencies - #29302, thanks @JReinhold!
Webpack: Fix export 'act' (imported as 'React4') was not found in 'react' errors in webpack - #29235, thanks @kasperpeulen!

</details>