Angular: Tailwind 4 compatibility

[valentinpalkovic]

Closes #30208

What I did

Angular's built-in Tailwind CSS integration doesn't support Tailwind 4's new PostCSS plugin architecture when using Webpack. When Tailwind 4 is detected in an Angular project, the build fails with errors because:

1. Incompatible API: Angular's getStylesConfig() tries to load Tailwind using the v3 API (require('tailwindcss')({ config }))
2. New Package Structure: Tailwind 4 uses @tailwindcss/postcss instead of the main tailwindcss package for PostCSS integration
3. Build Breakage: This causes webpack configuration to fail, preventing Storybook from building Angular projects with Tailwind 4

Solution

This PR implements a compatibility workaround that:

1. Detects Tailwind 4 by checking for the @tailwindcss/postcss package
2. Bypasses Angular's automatic detection by temporarily hiding Tailwind config files during getStylesConfig() execution
3. Manually injects the correct Tailwind 4 plugin into all PostCSS loader configurations
4. Preserves existing behavior for Tailwind v3 and other CSS frameworks

Checklist for Contributors

Testing

The changes in this PR are covered in the following automated tests:

• stories
• unit tests
• integration tests
• end-to-end tests

Manual testing

This section is mandatory for all contributions. If you believe no manual test is necessary, please state so explicitly. Thanks!

Documentation

• Add or update documentation reflecting your changes
• If you are deprecating/removing a feature, make sure to update
  MIGRATION.MD

Checklist for Maintainers

• When this PR is ready for testing, make sure to add ci:normal, ci:merged or ci:daily GH label to it to run a specific set of sandboxes. The particular set of sandboxes can be found in code/lib/cli-storybook/src/sandbox-templates.ts

• Make sure this PR contains one of the labels below:

  Available labels

  • bug: Internal changes that fixes incorrect behavior.
  • maintenance: User-facing maintenance tasks.
  • dependencies: Upgrading (sometimes downgrading) dependencies.
  • build: Internal-facing build tooling & test updates. Will not show up in release changelog.
  • cleanup: Minor cleanup style change. Will not show up in release changelog.
  • documentation: Documentation only changes. Will not show up in release changelog.
  • feature request: Introducing a new feature.
  • BREAKING CHANGE: Changes that break compatibility in some way with current major version.
  • other: Changes that don't fit in the above categories.

🦋 Canary release

This pull request has been released as version 0.0.0-pr-31759-sha-5376b07e. Try it out in a new sandbox by running npx [email protected] sandbox or in an existing project with npx [email protected] upgrade.

More information

Published version	0.0.0-pr-31759-sha-5376b07e
Triggered by	@valentinpalkovic
Repository	storybookjs/storybook
Branch	valentin/angular-tailwind-4-support
Commit	5376b07e
Datetime	Thu Jun 12 11:27:45 UTC 2025 (1749727665)
Workflow run	15609264774

To request a new release of this pull request, mention the @storybookjs/core team.

core team members can create a new canary release here or locally with gh workflow run --repo storybookjs/storybook canary-release-pr.yml --field pr=31759

Greptile Summary

Added compatibility support for Tailwind 4 in Angular Storybook projects by implementing a workaround for the new PostCSS plugin architecture.

• Detects Tailwind 4 by checking for @tailwindcss/postcss package presence
• Bypasses Angular's automatic detection by temporarily hiding Tailwind config during getStylesConfig() execution
• Manually injects Tailwind 4 PostCSS plugin into webpack configurations
• Maintains backward compatibility with Tailwind v3 projects
• Fixes build failures caused by Angular's incompatible v3 API usage (require('tailwindcss')({ config }))

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[nx-cloud]

View your CI Pipeline Execution ↗ for commit c1026b8.

Command	Status	Duration	Result
nx run-many -t build --parallel=3	✅ Succeeded	1m 18s	View ↗

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☁️ Nx Cloud last updated this comment at 2025-06-16 06:36:27 UTC