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fix(router-core): update ErrorRouteComponent to support generic error type #4727

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fix(router-core): update ErrorRouteComponent to support generic error type #4727

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6 changes: 4 additions & 2 deletions packages/react-router/src/route.tsx
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Original file line number Diff line number Diff line change
Expand Up @@ -49,7 +49,7 @@ import type { LinkComponentRoute } from './link'
declare module '@tanstack/router-core' {
export interface UpdatableRouteOptionsExtensions {
component?: RouteComponent
errorComponent?: false | null | ErrorRouteComponent
errorComponent?: false | null | ErrorRouteComponent<any>
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Is there a reason we wouldn't add the TError generic?

export interface UpdatableRouteOptionsExtensions<TError = Error> {
    errorComponent?: false | null | ErrorRouteComponent<TError>

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@leesb971204 leesb971204 Jul 21, 2025 •
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Is there a reason we wouldn't add the TError generic?

export interface UpdatableRouteOptionsExtensions<TError = Error> {
    errorComponent?: false | null | ErrorRouteComponent<TError>

If we make this change, wouldn’t it cause a type error in the errorComponent?
스크린샷 2025-07-21 오후 9 18 39

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@michaelbull

Do you have any additional ideas regarding this?

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Not really sure to be honest. Its unclear to me why that would cause a compiler error, and I explicitly use code-based routing (createRoute) not file based. I suspect you would have to chase the generic error type onto UpdatableRouteOptionsExtensions as well, but now I'm starting to second guess following this through.

I would defer to @schiller-manuel.

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@michaelbull

UpdatableRouteOptionsExtensions is not explicitly used in user code.
So if we declare it as UpdatableRouteOptionsExtensions<TError = Error>, the ErrorRouteComponent will always be inferred with Error as its generic type.
As a result, if the user specifies a type like ErrorComponentProps<string>, it will cause a type error—since Error is not compatible with string.

In conclusion, my personal opinion is that ErrorRouteComponent<any> is the appropriate way to declare it. What are your thoughts on this?

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@michaelbull

UpdatableRouteOptionsExtensions is not explicitly used in user code. So if we declare it as UpdatableRouteOptionsExtensions<TError = Error>, the ErrorRouteComponent will always be inferred with Error as its generic type. As a result, if the user specifies a type like ErrorComponentProps<string>, it will cause a type error—since Error is not compatible with string.

In conclusion, my personal opinion is that ErrorRouteComponent<any> is the appropriate way to declare it. What are your thoughts on this?

스크린샷 2025-07-30 오전 9 54 37

Additional note:
The same type error also occurs with createRoute.

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I don’t think this approach can fundamentally solve the problem, as it changes the errorComponent’s props type to any.

notFoundComponent?: NotFoundRouteComponent
pendingComponent?: RouteComponent
}
Expand Down Expand Up @@ -555,7 +555,9 @@ export type AsyncRouteComponent<TProps> = RouteTypes<TProps>['component'] & {

export type RouteComponent = AsyncRouteComponent<{}>

export type ErrorRouteComponent = AsyncRouteComponent<ErrorComponentProps>
export type ErrorRouteComponent<TError = Error> = AsyncRouteComponent<
ErrorComponentProps<TError>
>

export type NotFoundRouteComponent = RouteTypes<NotFoundRouteProps>['component']

Expand Down
6 changes: 4 additions & 2 deletions packages/solid-router/src/route.tsx
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -49,7 +49,7 @@ import type { LinkComponentRoute } from './link'
declare module '@tanstack/router-core' {
export interface UpdatableRouteOptionsExtensions {
component?: RouteComponent
errorComponent?: false | null | ErrorRouteComponent
errorComponent?: false | null | ErrorRouteComponent<any>
notFoundComponent?: NotFoundRouteComponent
pendingComponent?: RouteComponent
}
Expand Down Expand Up @@ -499,7 +499,9 @@ export type AsyncRouteComponent<TProps> = RouteTypes<TProps>['component'] & {

export type RouteComponent = AsyncRouteComponent<{}>

export type ErrorRouteComponent = AsyncRouteComponent<ErrorComponentProps>
export type ErrorRouteComponent<TError = Error> = AsyncRouteComponent<
ErrorComponentProps<TError>
>

export type NotFoundRouteComponent = RouteTypes<NotFoundRouteProps>['component']

Expand Down