Build: Fix react native expo e2e tests

[yannbf]

Closes #

What I did

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 PR does not have a canary release associated. You can request a canary release of this pull request by mentioning the @storybookjs/core team here.

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

Greptile Summary

This PR fixes end-to-end test failures for the React Native Expo template by making two targeted changes. The first change improves the robustness of the isReactSandbox utility function by refactoring it to use explicit null checking and optional chaining, preventing runtime errors when template lookups fail. The second change modifies the React Native Expo sandbox template creation script to establish the expected directory structure by moving the default app directory into src/app after project creation.

These changes address infrastructure issues in the testing pipeline where the e2e tests expected a specific project structure that wasn't being created by the default create-expo-app command. The utility function improvement adds defensive programming practices that make the template lookup more resilient to edge cases. Both changes are focused on internal testing infrastructure and don't affect user-facing functionality.

PR Description Notes:

• The PR description is missing details about what was actually done - the "What I did" section is empty
• No manual testing steps are provided despite the checklist requirement
• No automated test coverage is indicated

Confidence score: 4/5

• This PR is safe to merge with low risk of production issues
• Score reflects solid defensive programming improvements and targeted test infrastructure fixes
• Pay attention to the React Native Expo template configuration and utility function error handling

[greptile-apps]

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[nx-cloud]

View your CI Pipeline Execution ↗ for commit 8023f88

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nx run-many -t build -c production --parallel=3	✅ Succeeded	2s	View ↗

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☁️ Nx Cloud last updated this comment at 2025-08-11 16:36:56 UTC

[storybook-app-bot]

Package Benchmarks

^{Commit: 8023f88, ran on 11 August 2025 at 16:27:45 UTC}

The following packages have significant changes to their size or dependencies:

storybook

	Before	After	Difference
Dependency count	51	51	0
Self size	41.74 MB	41.75 MB	🚨 +15 KB 🚨
Dependency size	18.13 MB	18.13 MB	0 B
Bundle Size Analyzer	Link	Link

sb

	Before	After	Difference
Dependency count	52	52	0
Self size	1 KB	1 KB	0 B
Dependency size	59.87 MB	59.89 MB	🚨 +15 KB 🚨
Bundle Size Analyzer	Link	Link

@storybook/cli

	Before	After	Difference
Dependency count	220	220	0
Self size	585 KB	585 KB	🚨 +24 B 🚨
Dependency size	104.37 MB	104.39 MB	🚨 +15 KB 🚨
Bundle Size Analyzer	Link	Link

@storybook/codemod

	Before	After	Difference
Dependency count	189	189	0
Self size	31 KB	31 KB	0 B
Dependency size	88.45 MB	88.46 MB	🚨 +15 KB 🚨
Bundle Size Analyzer	Link	Link