docs(react-start): serialization adapters

[m9tdev]

Added an example on how to add serialization adapters for React Start. Not 100% sure if the right place is in the server function docs. LMK otherwise!

[coderabbitai]

Walkthrough

Documentation update adds a new "Custom serialization adapters" section for server functions, including usage examples and serialization behavior notes. The identical content appears in two separate locations within the document.

Changes

Cohort / File(s)	Summary
Server Functions Documentation docs/start/framework/react/guide/server-functions.md	Added "Custom serialization adapters" section with example showing bigint adapter definition and start configuration integration; content duplicated in two document locations

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~5 minutes

• Note: Verify whether the duplication of identical content in two locations is intentional or if one instance should be removed for maintainability

Possibly related PRs

• fix: merge serializationAdapters from createStart getOptions and router.options #5321 — Runtime implementation of custom serialization adapters that merges serializationAdapters from createStart/getOptions and router.options, directly corresponding to the adapter usage patterns documented here.

Poem

🐰 Serialization secrets now unfold,
Adapters guide the bigint and bold,
Two places blessed with adapter lore,
Server functions documented to the core!

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 PR title clearly and concisely summarizes the main change: adding documentation about serialization adapters for React Start, directly aligned with the file modifications.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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📜 Recent review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between dfb4f9a and 86875e6.

📒 Files selected for processing (1)

• docs/start/framework/react/guide/server-functions.md (1 hunks)

🧰 Additional context used

📓 Path-based instructions (2)

docs/**/*.{md,mdx}

📄 CodeRabbit inference engine (AGENTS.md)

Use internal docs links relative to the docs/ folder (e.g., ./guide/data-loading)

Files:

• docs/start/framework/react/guide/server-functions.md

docs/{router,start}/**

📄 CodeRabbit inference engine (AGENTS.md)

Place router docs under docs/router/ and start framework docs under docs/start/

Files:

• docs/start/framework/react/guide/server-functions.md

🧠 Learnings (1)

📓 Common learnings

Learnt from: CR
Repo: TanStack/router PR: 0
File: AGENTS.md:0-0
Timestamp: 2025-09-23T17:36:12.598Z
Learning: Applies to docs/{router,start}/** : Place router docs under docs/router/ and start framework docs under docs/start/

🔇 Additional comments (2)

docs/start/framework/react/guide/server-functions.md (2)

273-296: Code example is well-structured and follows sensible patterns.

The BigInt serialization adapter example is clear, the implementation is correct, and the integration into startInstance via serializationAdapters is properly documented. The section fits naturally within the Advanced Topics area.

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273-296: ****

The duplication concern in the review comment is unsupported. The verification shows that all references to "Custom serialization adapters," "bigIntAdapter," and "createSerializationAdapter" appear only once, within the single section at lines 273-296. There is no evidence of this content being repeated elsewhere in the document. The AI-generated summary cited in the review comment was inaccurate.

Likely an incorrect or invalid review comment.

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[birkskyum]

@m9tdev can you add the same to the solid docs so they stay in sync?

[schiller-manuel]

we need to document serialization adapters more generally, not just for server functions. they apply for beforeLoad and loader as well. a separate doc page should be added for this. want to do this when i find the time :)