fix(types): allow undefined for trailing wildcard params

[bytaesu]

• Closes Trailing wildcard param types do not include undefined #197

Summary by CodeRabbit

• New Features

  • Route parameters captured by trailing wildcards can now be optional when no value is present.
  • Route matching correctly handles wildcard patterns with trailing slashes or empty segments.

• Tests

  • Added coverage for optional wildcard captures and trailing-slash route patterns.
  • Updated type checks to reflect potentially undefined wildcard parameters.

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.

[coderabbitai]

📝 Walkthrough

Walkthrough

Trailing wildcard parameters now allow undefined in public route types. Type-level and runtime tests cover wildcard patterns that match empty trailing segments, while the match strategy contract reflects optional parameter values.

Changes

Trailing wildcard parameter types

Layer / File(s)	Summary
Trailing wildcard type inference src/types.ts	MatchedRoute.params and trailing wildcard keys in InferRouteParams now use string | undefined; other parameters remain string.
Runtime and type-level validation test/find.test.ts, test/types.test-d.ts, test/wpt.test.ts	Tests cover empty trailing wildcard matches, optional wildcard captures, and the widened match strategy parameter contract.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related PRs

• h3js/rou3#195: Covers trailing empty-segment handling that determines whether wildcard captures exist.

Suggested reviewers: copilot, pi0

Poem

A rabbit hops through /segment bright,
Finds an empty tail in the moonlit night.
“Undefined,” whispers the wildcard free,
Now types match reality.
Hop, hop—safer routes for me!

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely summarizes the main change: trailing wildcard params now allow undefined.
Linked Issues check	✅ Passed	The type updates and tests match #197 by making trailing wildcard params infer string | undefined and reflect runtime behavior.
Out of Scope Changes check	✅ Passed	The changes stay focused on route param typing and corresponding tests, with no obvious unrelated additions.
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

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[coderabbitai]

🧹 Nitpick comments (2)

src/types.ts (1)

27-27: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

Add a regression assertion for MatchedRoute.params.

The supplied test/types.test-d.ts verifies InferRouteParams but not this changed public type. Add an assertion such as MatchedRoute["params"] equals Record<string, string | undefined> | undefined so the runtime { "0": undefined } contract cannot regress.

As per path instructions, test/**/*.{ts,d.ts} must maintain regression coverage and verify public API types there.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@src/types.ts` at line 27, Add a type-level regression assertion in
test/types.test-d.ts for MatchedRoute["params"], verifying it equals
Record<string, string | undefined> | undefined. Keep the existing
InferRouteParams assertions intact and ensure the test covers the public
MatchedRoute params contract, including undefined values.

Source: Path instructions

test/wpt.test.ts (1)

263-266: 🗄️ Data Integrity & Integration | 🔵 Trivial | ⚡ Quick win

Align normalizeGroups with the widened match params contract.

MatchStrategy.match allows Record<string, string | undefined>, so match.groups values may be missing/undefined. Update normalizeGroups to accept and return groups containing undefined values instead of hiding that possibility with Record<string, string>.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@test/wpt.test.ts` around lines 263 - 266, Update normalizeGroups to accept
and return group records typed as Record<string, string | undefined>, matching
the widened params contract of MatchStrategy.match. Preserve its existing
normalization behavior while allowing missing or undefined group values instead
of narrowing them to strings.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@src/types.ts`:
- Line 27: Add a type-level regression assertion in test/types.test-d.ts for
MatchedRoute["params"], verifying it equals Record<string, string | undefined> |
undefined. Keep the existing InferRouteParams assertions intact and ensure the
test covers the public MatchedRoute params contract, including undefined values.

In `@test/wpt.test.ts`:
- Around line 263-266: Update normalizeGroups to accept and return group records
typed as Record<string, string | undefined>, matching the widened params
contract of MatchStrategy.match. Preserve its existing normalization behavior
while allowing missing or undefined group values instead of narrowing them to
strings.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 262c5260-13d6-437c-8ab0-dfa52c867f38

📥 Commits

Reviewing files that changed from the base of the PR and between 39b0e9b and 6d5f06f.

📒 Files selected for processing (4)

• src/types.ts
• test/find.test.ts
• test/types.test-d.ts
• test/wpt.test.ts