Core: Make subtype an optional property on an index input

[JReinhold]

What I did

Made subtype optional, defaulting to 'story' on index inputs. This doesn't change what is actually in the index, only what indexers are required to specify.

Checklist for Contributors

Testing

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

• stories
• unit tests
• integration tests
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Documentation

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

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  • bug: Internal changes that fixes incorrect behavior.
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  • dependencies: Upgrading (sometimes downgrading) dependencies.
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🦋 Canary release

This pull request has been released as version 0.0.0-pr-32602-sha-16d7f80f. 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-32602-sha-16d7f80f
Triggered by	@JReinhold
Repository	storybookjs/storybook
Branch	jeppe/optional-subtype
Commit	16d7f80f
Datetime	Thu Oct 2 19:24:10 UTC 2025 (1759433050)
Workflow run	18203399574

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 publish.yml --field pr=32602

Summary by CodeRabbit

• New Features

  • Indexing now accepts entries without a subtype; unspecified subtype defaults to "story".
  • Index entries may include optional component path and export name metadata.

• Bug Fixes

  • Improved handling and classification for entries with the "test" subtype.

• Documentation

  • Indexer docs updated to describe the optional experimental subtype field, its default, and examples.

[coderabbitai]

📝 Walkthrough

Walkthrough

Story index handling was adjusted: StoryIndexInput.subtype became optional, StoryIndexGenerator computes an effective subtype (defaulting to 'story'), casts indexer output to StoryIndexInput[], defers setting parent/exportName/componentPath onto entries, and a renderer preset stopped emitting subtype for story entries. Types and docs updated.

Changes

Cohort / File(s)	Summary
Core: Story index generator code/core/src/core-server/utils/StoryIndexGenerator.ts	Cast indexer.createIndex result to StoryIndexInput[]; compute local subtype = input.subtype ?? 'story'; use subtype when building entries; defer post-assignments of parent, parentName, and exportName; maintain entry structure otherwise.
Types: indexer input & entry code/core/src/types/modules/indexer.ts	Make StoryIndexInput.subtype optional (`subtype?: 'story'
Docs: API indexers docs/api/main-config/main-config-indexers.mdx	Document `subtype?: 'story'
Renderers: preset output code/renderers/server/src/preset.ts	Remove emitting subtype: 'story' from indexer entries produced by the experimental indexer preset; other fields unchanged.

Sequence Diagram(s)

sequenceDiagram
  autonumber
  participant Indexer as Indexer (produces IndexInput)
  participant SIG as StoryIndexGenerator
  participant Output as Story Index

  Note over Indexer: Emits IndexInput with optional `subtype` and other fields
  Indexer->>SIG: IndexInput { type, subtype?, componentPath?, exportName?, ... }

  rect rgba(200,230,210,0.25)
    Note over SIG: Normalize and construct entry
    SIG->>SIG: cast inputs to StoryIndexInput[]
    SIG->>SIG: subtype := input.subtype ?? 'story'
    SIG->>SIG: build entry using subtype and other fields
    SIG->>SIG: if subtype === 'test' then assign parent/parentName
    SIG->>SIG: if input.exportName then assign exportName
  end

  SIG->>Output: emit StoryIndexEntry (with optional componentPath/exportName/subtype for tests)

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Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• Core: Add missing subtype props #32490 — Related edits to StoryIndexGenerator and subtype propagation/handling.
• CSF: Add Storybook test syntax (Storybook v10) #32455 — Overlapping changes to story indexing surface and subtype in indexer/preset.

Pre-merge checks and finishing touches

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title Check	✅ Passed	The title succinctly and accurately describes the primary change of making the subtype property optional on index input objects within the core module, matching both the raw code updates and the PR objectives. It is clear and specific without extraneous information.
Docstring Coverage	✅ Passed	No functions found in the changes. Docstring coverage check skipped.

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📒 Files selected for processing (3)

• code/core/src/core-server/utils/StoryIndexGenerator.ts (4 hunks)
• code/core/src/types/modules/indexer.ts (2 hunks)
• code/renderers/server/src/preset.ts (0 hunks)

💤 Files with no reviewable changes (1)

• code/renderers/server/src/preset.ts

🚧 Files skipped from review as they are similar to previous changes (1)

• code/core/src/core-server/utils/StoryIndexGenerator.ts

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**/*.{ts,tsx,js,jsx}

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Files:

• code/core/src/types/modules/indexer.ts

**/*.{ts,tsx}

📄 CodeRabbit inference engine (.github/copilot-instructions.md)

Fix type errors and prefer precise typings instead of using any or suppressions, consistent with strict mode

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🔇 Additional comments (2)

code/core/src/types/modules/indexer.ts (2)

139-139: LGTM: Optional subtype input defaults to 'story' at runtime.

StoryIndexGenerator applies input.subtype ?? 'story' and no direct unguarded input.subtype accesses remain, preserving type safety.

---

77-78: No action needed: exportName on input and entry is the same field carried through—no ambiguity in usage or purpose.

---

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[coderabbitai]

Actionable comments posted: 2

🧹 Nitpick comments (1)

docs/api/main-config/main-config-indexers.mdx (1)

499-499: Remove trailing blank line.

This appears to be an unintentional whitespace change.

Apply this diff:

-
 </details>

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Reviewing files that changed from the base of the PR and between 764c7c2 and f265de0.

📒 Files selected for processing (3)

• code/core/src/core-server/utils/StoryIndexGenerator.ts (2 hunks)
• code/core/src/types/modules/indexer.ts (1 hunks)
• docs/api/main-config/main-config-indexers.mdx (3 hunks)

🧰 Additional context used

📓 Path-based instructions (2)

**/*.{ts,tsx,js,jsx}

📄 CodeRabbit inference engine (.github/copilot-instructions.md)

Adhere to ESLint and Prettier rules across all JS/TS source files

Files:

• code/core/src/types/modules/indexer.ts
• code/core/src/core-server/utils/StoryIndexGenerator.ts

**/*.{ts,tsx}

📄 CodeRabbit inference engine (.github/copilot-instructions.md)

Fix type errors and prefer precise typings instead of using any or suppressions, consistent with strict mode

Files:

• code/core/src/types/modules/indexer.ts
• code/core/src/core-server/utils/StoryIndexGenerator.ts

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (3)

• GitHub Check: Danger JS
• GitHub Check: normal
• GitHub Check: Core Unit Tests, windows-latest

🔇 Additional comments (2)

code/core/src/core-server/utils/StoryIndexGenerator.ts (1)

442-462: LGTM! Clean implementation of optional subtype with sensible defaults.

The logic correctly:

• Defaults to 'story' when input.type !== 'story'
• Falls back to 'story' when input.subtype is undefined
• Uses the computed subtype consistently throughout the entry construction

The conditional at line 457 properly uses the computed subtype value instead of the raw input.subtype.

code/core/src/types/modules/indexer.ts (1)

137-137: LGTM! Type definition correctly reflects optional nature.

The optional marker correctly aligns with the PR objective and the default handling logic in StoryIndexGenerator.ts.

[nx-cloud]

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☁️ Nx Cloud last updated this comment at 2025-10-03 08:31:39 UTC

[kylegach]

Thanks for updating the API reference. I made some suggested changes that need to be addressed prior to merging.

[storybook-bot]

Failed to publish canary version of this pull request, triggered by @JReinhold. See the failed workflow run at: https://github.com/storybookjs/storybook/actions/runs/18203285428