Reviewing files that changed from the base of the PR and between fdbbb5f and 075d557.

• src/event.ts
• src/h3.ts
• src/types/_utils.ts
• src/types/context.ts
• src/types/h3.ts
• src/utils/request.ts
• test/unit/types.test-d.ts

src/utils/request.ts (2)

143-150: Well-structured overloads for type inference.

The overloads correctly distinguish between H3Event (with inferred route params) and generic HTTPEvent (with fallback type). This enables proper type narrowing when using typed events from route handlers.

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269-283: Good overload design for getRouterParam.

The generic constraint on Key ensures autocomplete for valid parameter names when using typed events, while the HTTPEvent overload provides flexibility for untyped contexts.

src/event.ts (1)

58-62: Effective use of intersection type for precise params typing.

The conditional type _RequestT["routerParams"] extends undefined ? undefined : _RequestT["routerParams"] correctly handles the distinction between routes with and without parameters, ensuring params is undefined for static routes and strongly typed for dynamic routes.

src/types/context.ts (1)

5-13: Clean generic extension maintaining backward compatibility.

The default TParams = Record<string, string> preserves existing behavior for consumers not using typed route parameters, while enabling precise typing when needed.

src/types/_utils.ts (1)

5-11: Well-designed type utility for route parameter inference.

The RouteParams type correctly:

1. Uses Simplify to flatten the inferred type for better IDE tooltips
2. Returns undefined for static routes (empty params) via keyof _Simplified extends never
3. Preserves the inferred parameter shape for dynamic routes

This aligns well with the typing in H3Event.context.params.

src/h3.ts (2)

171-205: Correct overload structure for route parameter inference.

The overload ordering is correct: the generic Route extends string overload is listed first and will match when TypeScript can infer a literal string type. The fallback string overload handles dynamic route strings. The cast on line 200 is necessary since the implementation must handle both handler types.

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207-209: The typed overload for the all() method already exists in src/types/h3.ts (lines 214-220) with proper generic type support and a fallback overload. No changes are needed.

Likely an incorrect or invalid review comment.

test/unit/types.test-d.ts (2)

131-195: Comprehensive type tests for router params inference.

The tests thoroughly cover:

• Explicit routerParams in EventHandlerRequest
• Default fallback to Record<string, string> | undefined
• Helper function type inference (getRouterParams, getRouterParam)
• Autocomplete constraint on getRouterParam key parameter

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197-309: Good coverage for app route inference scenarios.

The tests validate inference across HTTP methods (get, post, on), multiple dynamic segments, static routes (correctly typed as undefined), and the important edge case of reusable handlers maintaining generic types while inline handlers get full inference.

src/types/h3.ts (2)

26-49: Well-documented interface design for method handlers.

The H3HandlerInterface pattern with the This extends H3 generic constraint is a clever solution to maintain proper this typing. The documentation (lines 36-38) explaining why H3 isn't used directly in the return type is helpful for maintainability.

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223-231: HTTP method properties enable route-typed overloads.

Changing from method declarations to H3HandlerInterface<this> properties allows the two-signature callable interface to work correctly, providing both typed inference for literal route strings and fallback for dynamic routes.