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Lit

@trpc12/tanstack-lit-query: a provider element for the client, useTrpc(this) in elements, and createSubscriptionController.

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@trpc12/tanstack-lit-query re-exports @trpc12/tanstack-query and adds a provider element and @lit/context consumers for a client and its helpers, and a createSubscriptionController. Without a provider, createTrpcQueryUtils({ client }) works in Lit too.

Not on npm yet
pnpm add @trpc12/trpc @trpc12/tanstack-lit-query @tanstack/lit-query @lit/context
npm install @trpc12/trpc @trpc12/tanstack-lit-query @tanstack/lit-query @lit/context
yarn add @trpc12/trpc @trpc12/tanstack-lit-query @tanstack/lit-query @lit/context
bun add @trpc12/trpc @trpc12/tanstack-lit-query @tanstack/lit-query @lit/context

Provide the client

createTrpcContext takes the type of the function that makes the client (or of the client, or the router), so the helpers get what its links declare. Its TrpcProvider element isn't registered: define it under a tag of your choice, as TanStack's QueryClientProvider, and set its client as a property, inside TanStack's provider:

// trpc.ts
const 
const makeClient: () => TrpcClient<{
    post: {
        byId: BuildProcedure<InputDef<RootDef<Context, {}>, ZodObject<{
            id: ZodString;
        }, $strip>>, "query", {
            output: Post;
            errors: TrpcError<"NOT_FOUND", {
                id: string;
            }>;
            services: never;
            unmapped: never;
        }>;
        list: BuildProcedure<RootDef<Context, {}>, "query", {
            output: Post[];
            errors: never;
            services: never;
            unmapped: never;
        }>;
        create: BuildProcedure<InputDef<With<RootDef<Context, {}>, {
            ctx: Context;
            ctxAdded: {
                ...;
            };
            inputOut: Unset;
            errors: TrpcError<...>;
            shorts: never;
        }>, ZodObject<...>>, "mutation", {
            ...;
        }>;
    };
}, {}, undefined, LinksTypes<...>>
makeClient = () =>
  
createTrpcClient<RouterType<{
    post: {
        byId: BuildProcedure<InputDef<RootDef<Context, {}>, ZodObject<{
            id: ZodString;
        }, $strip>>, "query", {
            output: Post;
            errors: TrpcError<"NOT_FOUND", {
                id: string;
            }>;
            services: never;
            unmapped: never;
        }>;
        list: BuildProcedure<RootDef<Context, {}>, "query", {
            output: Post[];
            errors: never;
            services: never;
            unmapped: never;
        }>;
        create: BuildProcedure<InputDef<With<RootDef<Context, {}>, {
            ctx: Context;
            ctxAdded: {
                ...;
            };
            inputOut: Unset;
            errors: TrpcError<...>;
            shorts: never;
        }>, ZodObject<...>>, "mutation", {
            ...;
        }>;
    };
}>, readonly [...]>(opts: TypedClientOptions<...>): TrpcClient<...>
createTrpcClient({
    
TypedClientOptions<RouterType<{ post: { byId: BuildProcedure<InputDef<RootDef<Context, {}>, ZodObject<{ id: ZodString; }, $strip>>, "query", { output: Post; errors: TrpcError<...>; services: never; unmapped: never; }>; list: BuildProcedure<...>; create: BuildProcedure<...>; }; }>, readonly [...]>.router: RouterType<{
    post: {
        byId: BuildProcedure<InputDef<RootDef<Context, {}>, ZodObject<{
            id: ZodString;
        }, $strip>>, "query", {
            output: Post;
            errors: TrpcError<"NOT_FOUND", {
                id: string;
            }>;
            services: never;
            unmapped: never;
        }>;
        list: BuildProcedure<RootDef<Context, {}>, "query", {
            output: Post[];
            errors: never;
            services: never;
            unmapped: never;
        }>;
        create: BuildProcedure<InputDef<With<RootDef<Context, {}>, {
            ctx: Context;
            ctxAdded: {
                ...;
            };
            inputOut: Unset;
            errors: TrpcError<...>;
            shorts: never;
        }>, ZodObject<...>>, "mutation", {
            ...;
        }>;
    };
}>
router: 
routerType<{
    post: {
        byId: BuildProcedure<InputDef<RootDef<Context, {}>, ZodObject<{
            id: ZodString;
        }, $strip>>, "query", {
            output: Post;
            errors: TrpcError<"NOT_FOUND", {
                id: string;
            }>;
            services: never;
            unmapped: never;
        }>;
        list: BuildProcedure<RootDef<Context, {}>, "query", {
            output: Post[];
            errors: never;
            services: never;
            unmapped: never;
        }>;
        create: BuildProcedure<InputDef<With<RootDef<Context, {}>, {
            ctx: Context;
            ctxAdded: {
                ...;
            };
            inputOut: Unset;
            errors: TrpcError<...>;
            shorts: never;
        }>, ZodObject<...>>, "mutation", {
            ...;
        }>;
    };
}>(): RouterType<...>
routerType<
type AppRouter = {
    post: {
        byId: BuildProcedure<InputDef<RootDef<Context, {}>, ZodObject<{
            id: ZodString;
        }, $strip>>, "query", {
            output: Post;
            errors: TrpcError<"NOT_FOUND", {
                id: string;
            }>;
            services: never;
            unmapped: never;
        }>;
        list: BuildProcedure<RootDef<Context, {}>, "query", {
            output: Post[];
            errors: never;
            services: never;
            unmapped: never;
        }>;
        create: BuildProcedure<InputDef<With<RootDef<Context, {}>, {
            ctx: Context;
            ctxAdded: {
                ...;
            };
            inputOut: Unset;
            errors: TrpcError<...>;
            shorts: never;
        }>, ZodObject<...>>, "mutation", {
            ...;
        }>;
    };
}
AppRouter>(),
    
TypedClientOptions<RouterType<{ post: { byId: BuildProcedure<InputDef<RootDef<Context, {}>, ZodObject<{ id: ZodString; }, $strip>>, "query", { output: Post; errors: TrpcError<...>; services: never; unmapped: never; }>; list: BuildProcedure<...>; create: BuildProcedure<...>; }; }>, readonly [...]>.links: readonly [TrpcLink<{
    form: JsonForm;
    provides: "response";
}, any>]
links: [
httpLink<{
    url: string;
}>(opts: {
    url: string;
}): TrpcLink<{
    form: JsonForm;
    provides: "response";
}, any>
httpLink({ url: stringurl: '/trpc' })],
  });
export const { 
const TrpcProvider: new () => TrpcProviderElement<{
    post: {
        byId: BuildProcedure<InputDef<RootDef<Context, {}>, ZodObject<{
            id: ZodString;
        }, $strip>>, "query", {
            output: Post;
            errors: TrpcError<"NOT_FOUND", {
                id: string;
            }>;
            services: never;
            unmapped: never;
        }>;
        list: BuildProcedure<RootDef<Context, {}>, "query", {
            output: Post[];
            errors: never;
            services: never;
            unmapped: never;
        }>;
        create: BuildProcedure<InputDef<With<RootDef<Context, {}>, {
            ctx: Context;
            ctxAdded: {
                ...;
            };
            inputOut: Unset;
            errors: TrpcError<...>;
            shorts: never;
        }>, ZodObject<...>>, "mutation", {
            ...;
        }>;
    };
}, {}, LinksTypes<...>>
TrpcProvider, 
const useTrpc: (host: ReactiveElement) => TrpcQueryUtilsFor<{
    post: {
        byId: BuildProcedure<InputDef<RootDef<Context, {}>, ZodObject<{
            id: ZodString;
        }, $strip>>, "query", {
            output: Post;
            errors: TrpcError<"NOT_FOUND", {
                id: string;
            }>;
            services: never;
            unmapped: never;
        }>;
        list: BuildProcedure<RootDef<Context, {}>, "query", {
            output: Post[];
            errors: never;
            services: never;
            unmapped: never;
        }>;
        create: BuildProcedure<InputDef<With<RootDef<Context, {}>, {
            ...;
        }>, ZodObject<...>>, "mutation", {
            ...;
        }>;
    };
}, {}, LinksTypes<...>>
useTrpc, 
const useTrpcClient: (host: ReactiveElement) => TrpcClient<{
    post: {
        byId: BuildProcedure<InputDef<RootDef<Context, {}>, ZodObject<{
            id: ZodString;
        }, $strip>>, "query", {
            output: Post;
            errors: TrpcError<"NOT_FOUND", {
                id: string;
            }>;
            services: never;
            unmapped: never;
        }>;
        list: BuildProcedure<RootDef<Context, {}>, "query", {
            output: Post[];
            errors: never;
            services: never;
            unmapped: never;
        }>;
        create: BuildProcedure<InputDef<With<RootDef<Context, {}>, {
            ...;
        }>, ZodObject<...>>, "mutation", {
            ...;
        }>;
    };
}, {}, undefined, LinksTypes<...>>
useTrpcClient } =
  
createTrpcContext<() => TrpcClient<{
    post: {
        byId: BuildProcedure<InputDef<RootDef<Context, {}>, ZodObject<{
            id: ZodString;
        }, $strip>>, "query", {
            output: Post;
            errors: TrpcError<"NOT_FOUND", {
                id: string;
            }>;
            services: never;
            unmapped: never;
        }>;
        list: BuildProcedure<RootDef<Context, {}>, "query", {
            output: Post[];
            errors: never;
            services: never;
            unmapped: never;
        }>;
        create: BuildProcedure<InputDef<With<RootDef<Context, {}>, {
            ctx: Context;
            ctxAdded: {
                ...;
            };
            inputOut: Unset;
            errors: TrpcError<...>;
            shorts: never;
        }>, ZodObject<...>>, "mutation", {
            ...;
        }>;
    };
}, {}, undefined, LinksTypes<...>>>(opts?: TrpcContextOptions): TrpcLitContext<...>
createTrpcContext<typeof 
const makeClient: () => TrpcClient<{
    post: {
        byId: BuildProcedure<InputDef<RootDef<Context, {}>, ZodObject<{
            id: ZodString;
        }, $strip>>, "query", {
            output: Post;
            errors: TrpcError<"NOT_FOUND", {
                id: string;
            }>;
            services: never;
            unmapped: never;
        }>;
        list: BuildProcedure<RootDef<Context, {}>, "query", {
            output: Post[];
            errors: never;
            services: never;
            unmapped: never;
        }>;
        create: BuildProcedure<InputDef<With<RootDef<Context, {}>, {
            ctx: Context;
            ctxAdded: {
                ...;
            };
            inputOut: Unset;
            errors: TrpcError<...>;
            shorts: never;
        }>, ZodObject<...>>, "mutation", {
            ...;
        }>;
    };
}, {}, undefined, LinksTypes<...>>
makeClient>();
var customElements: CustomElementRegistrycustomElements.CustomElementRegistry.define(name: string, constructor: CustomElementConstructor, options?: ElementDefinitionOptions): voiddefine('trpc-provider', 
const TrpcProvider: new () => TrpcProviderElement<{
    post: {
        byId: BuildProcedure<InputDef<RootDef<Context, {}>, ZodObject<{
            id: ZodString;
        }, $strip>>, "query", {
            output: Post;
            errors: TrpcError<"NOT_FOUND", {
                id: string;
            }>;
            services: never;
            unmapped: never;
        }>;
        list: BuildProcedure<RootDef<Context, {}>, "query", {
            output: Post[];
            errors: never;
            services: never;
            unmapped: never;
        }>;
        create: BuildProcedure<InputDef<With<RootDef<Context, {}>, {
            ctx: Context;
            ctxAdded: {
                ...;
            };
            inputOut: Unset;
            errors: TrpcError<...>;
            shorts: never;
        }>, ZodObject<...>>, "mutation", {
            ...;
        }>;
    };
}, {}, LinksTypes<...>>
TrpcProvider);

// app.ts
var customElements: CustomElementRegistrycustomElements.CustomElementRegistry.define(name: string, constructor: CustomElementConstructor, options?: ElementDefinitionOptions): voiddefine('query-client-provider', class QueryClientProviderQueryClientProvider);
const const queryClient: QueryClientqueryClient = new new QueryClient(config?: QueryClientConfig): QueryClientQueryClient();
const 
const client: TrpcClient<{
    post: {
        byId: BuildProcedure<InputDef<RootDef<Context, {}>, ZodObject<{
            id: ZodString;
        }, $strip>>, "query", {
            output: Post;
            errors: TrpcError<"NOT_FOUND", {
                id: string;
            }>;
            services: never;
            unmapped: never;
        }>;
        list: BuildProcedure<RootDef<Context, {}>, "query", {
            output: Post[];
            errors: never;
            services: never;
            unmapped: never;
        }>;
        create: BuildProcedure<InputDef<With<RootDef<Context, {}>, {
            ctx: Context;
            ctxAdded: {
                ...;
            };
            inputOut: Unset;
            errors: TrpcError<...>;
            shorts: never;
        }>, ZodObject<...>>, "mutation", {
            ...;
        }>;
    };
}, {}, undefined, LinksTypes<...>>
client = 
const makeClient: () => TrpcClient<{
    post: {
        byId: BuildProcedure<InputDef<RootDef<Context, {}>, ZodObject<{
            id: ZodString;
        }, $strip>>, "query", {
            output: Post;
            errors: TrpcError<"NOT_FOUND", {
                id: string;
            }>;
            services: never;
            unmapped: never;
        }>;
        list: BuildProcedure<RootDef<Context, {}>, "query", {
            output: Post[];
            errors: never;
            services: never;
            unmapped: never;
        }>;
        create: BuildProcedure<InputDef<With<RootDef<Context, {}>, {
            ctx: Context;
            ctxAdded: {
                ...;
            };
            inputOut: Unset;
            errors: TrpcError<...>;
            shorts: never;
        }>, ZodObject<...>>, "mutation", {
            ...;
        }>;
    };
}, {}, undefined, LinksTypes<...>>
makeClient();
const html: (strings: TemplateStringsArray, ...values: unknown[]) => TemplateResult<1>html`<query-client-provider .client=${const queryClient: QueryClientqueryClient}>
  <trpc-provider .client=${
const client: TrpcClient<{
    post: {
        byId: BuildProcedure<InputDef<RootDef<Context, {}>, ZodObject<{
            id: ZodString;
        }, $strip>>, "query", {
            output: Post;
            errors: TrpcError<"NOT_FOUND", {
                id: string;
            }>;
            services: never;
            unmapped: never;
        }>;
        list: BuildProcedure<RootDef<Context, {}>, "query", {
            output: Post[];
            errors: never;
            services: never;
            unmapped: never;
        }>;
        create: BuildProcedure<InputDef<With<RootDef<Context, {}>, {
            ctx: Context;
            ctxAdded: {
                ...;
            };
            inputOut: Unset;
            errors: TrpcError<...>;
            shorts: never;
        }>, ZodObject<...>>, "mutation", {
            ...;
        }>;
    };
}, {}, undefined, LinksTypes<...>>
client}><post-view></post-view></trpc-provider>
</query-client-provider>`;

context is the @lit/context key too, for @consume or a provider of your own.

Queries and mutations

Call useTrpc(this) in a field initializer. It resolves the helpers on first use, so use them once the element is connected: in render or in a controller's options function. Pass a function to createQueryController, so the options are read again on each update; a new input is a new key:

class class PostViewPostView extends class LitElementLitElement {
  static override 
PostView.properties: {
    postId: {};
}
properties = { postId: {}postId: {} };
  declare PostView.postId: stringpostId: string;

  
PostView.trpc: TrpcQueryUtilsFor<{
    post: {
        byId: BuildProcedure<InputDef<RootDef<Context, {}>, ZodObject<{
            id: ZodString;
        }, $strip>>, "query", {
            output: Post;
            errors: TrpcError<"NOT_FOUND", {
                id: string;
            }>;
            services: never;
            unmapped: never;
        }>;
        list: BuildProcedure<RootDef<Context, {}>, "query", {
            output: Post[];
            errors: never;
            services: never;
            unmapped: never;
        }>;
        create: BuildProcedure<InputDef<With<RootDef<Context, {}>, {
            ctx: Context;
            ctxAdded: {
                ...;
            };
            inputOut: Unset;
            errors: TrpcError<...>;
            shorts: never;
        }>, ZodObject<...>>, "mutation", {
            ...;
        }>;
    };
}, {}, {}>
trpc = 
const useTrpc: (host: ReactiveElement) => TrpcQueryUtilsFor<{
    post: {
        byId: BuildProcedure<InputDef<RootDef<Context, {}>, ZodObject<{
            id: ZodString;
        }, $strip>>, "query", {
            output: Post;
            errors: TrpcError<"NOT_FOUND", {
                id: string;
            }>;
            services: never;
            unmapped: never;
        }>;
        list: BuildProcedure<RootDef<Context, {}>, "query", {
            output: Post[];
            errors: never;
            services: never;
            unmapped: never;
        }>;
        create: BuildProcedure<InputDef<With<RootDef<Context, {}>, {
            ...;
        }>, ZodObject<...>>, "mutation", {
            ...;
        }>;
    };
}, {}, {}>
useTrpc(this);
  
PostView.post: QueryResultAccessor<{
    id: string;
    title: string;
    author: string | null;
    createdAt: string;
}, NonNullable<UnexpectedError | (TrpcError<"NOT_FOUND", {
    id: string;
}> & {
    readonly defined: true;
}) | (TrpcError<"BAD_REQUEST", InputValidationErrorData<{
    readonly code: "invalid_type";
    readonly expected: $ZodInvalidTypeExpected;
    readonly path: readonly [] | readonly ["id"];
    readonly message: string;
} | {
    readonly code: "too_big";
    readonly origin: "number" | "int" | "bigint" | "date" | "string" | "array" | "set" | "file" | (string & {});
    ... 4 more ...;
    readonly message: string;
} | ... 9 more ... | {
    ...;
}>> & {
    ...;
})>>
post = 
createQueryController<{
    id: string;
    title: string;
    author: string | null;
    createdAt: string;
}, NonNullable<UnexpectedError | (TrpcError<"NOT_FOUND", {
    id: string;
}> & {
    readonly defined: true;
}) | (TrpcError<"BAD_REQUEST", InputValidationErrorData<{
    readonly code: "invalid_type";
    readonly expected: $ZodInvalidTypeExpected;
    readonly path: readonly [] | readonly ["id"];
    readonly message: string;
} | {
    readonly code: "too_big";
    readonly origin: "number" | "int" | "bigint" | "date" | "string" | "array" | "set" | "file" | (string & {});
    ... 4 more ...;
    readonly message: string;
} | ... 9 more ... | {
    ...;
}>> & {
    ...;
})>, {
    id: string;
    title: string;
    author: string | null;
    createdAt: string;
}, {
    id: string;
    title: string;
    author: string | null;
    createdAt: string;
}, TrpcQueryKey & {
    ...;
}>(host: ReactiveControllerHost, options: Accessor<...>, queryClient?: QueryClient): QueryResultAccessor<...>
createQueryController(this, () =>
    this.
PostView.trpc: TrpcQueryUtilsFor<{
    post: {
        byId: BuildProcedure<InputDef<RootDef<Context, {}>, ZodObject<{
            id: ZodString;
        }, $strip>>, "query", {
            output: Post;
            errors: TrpcError<"NOT_FOUND", {
                id: string;
            }>;
            services: never;
            unmapped: never;
        }>;
        list: BuildProcedure<RootDef<Context, {}>, "query", {
            output: Post[];
            errors: never;
            services: never;
            unmapped: never;
        }>;
        create: BuildProcedure<InputDef<With<RootDef<Context, {}>, {
            ctx: Context;
            ctxAdded: {
                ...;
            };
            inputOut: Unset;
            errors: TrpcError<...>;
            shorts: never;
        }>, ZodObject<...>>, "mutation", {
            ...;
        }>;
    };
}, {}, {}>
trpc.
post: TrpcQueryUtils<ClientRouter<{
    byId: BuildProcedure<InputDef<RootDef<Context, {}>, ZodObject<{
        id: ZodString;
    }, $strip>>, "query", {
        output: Post;
        errors: TrpcError<"NOT_FOUND", {
            id: string;
        }>;
        services: never;
        unmapped: never;
    }>;
    list: BuildProcedure<RootDef<Context, {}>, "query", {
        output: Post[];
        errors: never;
        services: never;
        unmapped: never;
    }>;
    create: BuildProcedure<InputDef<With<RootDef<Context, {}>, {
        ctx: Context;
        ctxAdded: {
            ...;
        };
        inputOut: Unset;
        errors: TrpcError<...>;
        shorts: never;
    }>, ZodObject<...>>, "mutation", {
        ...;
    }>;
}, {}, undefined, {}>>
post.
byId: QueryProcedureUtils<{
    id: string;
}, {
    id: string;
    title: string;
    author: string | null;
    createdAt: string;
}, NonNullable<UnexpectedError | (TrpcError<"NOT_FOUND", {
    id: string;
}> & {
    readonly defined: true;
}) | (TrpcError<"BAD_REQUEST", InputValidationErrorData<{
    readonly code: "invalid_type";
    readonly expected: $ZodInvalidTypeExpected;
    readonly path: readonly [] | readonly ["id"];
    readonly message: string;
} | {
    readonly code: "too_big";
    readonly origin: "number" | "int" | "bigint" | "date" | "string" | "array" | "set" | "file" | (string & {});
    ... 4 more ...;
    readonly message: string;
} | ... 9 more ... | {
    ...;
}>> & {
    ...;
})>, Omit<...>>
byId.
QueryProcedureUtils<{ id: string; }, { id: string; title: string; author: string | null; createdAt: string; }, NonNullable<UnexpectedError | (TrpcError<"NOT_FOUND", { id: string; }> & { ...; }) | (TrpcError<...> & { ...; })>, Omit<...>>.queryOptions<{
    id: string;
    title: string;
    author: string | null;
    createdAt: string;
}>(opts: {
    input: {
        id: string;
    } | unique symbol;
} & ContextBag<Omit<NonNullable<{
    signal?: AbortSignal | undefined;
} & BuiltinCallOptions>, "signal" | "lastEventId">> & QueryOptionsIn<{
    id: string;
    title: string;
    author: string | null;
    createdAt: string;
}, NonNullable<UnexpectedError | (TrpcError<"NOT_FOUND", {
    id: string;
}> & {
    readonly defined: true;
}) | (TrpcError<"BAD_REQUEST", InputValidationErrorData<{
    readonly code: "invalid_type";
    readonly expected: $ZodInvalidTypeExpected;
    readonly path: readonly [] | readonly [...];
    readonly message: string;
} | ... 10 more ... | {
    ...;
}>> & {
    ...;
})>, {
    id: string;
    title: string;
    author: string | null;
    createdAt: string;
}>): QueryOptionsOut<...> (+1 overload)
queryOptions({ 
input: {
    id: string;
} | unique symbol
input: { id: stringid: this.PostView.postId: stringpostId } }),
  );
  
PostView.create: MutationResultAccessor<{
    id: string;
    title: string;
    author: string | null;
    createdAt: string;
}, (TrpcError<"NOT_FOUND" | "BAD_REQUEST" | "UNAUTHORIZED" | "PARSE_ERROR" | "UNSUPPORTED_PROTOCOL" | "PAYMENT_REQUIRED" | "FORBIDDEN" | "METHOD_NOT_SUPPORTED" | "TIMEOUT" | "CONFLICT" | "PRECONDITION_FAILED" | "PAYLOAD_TOO_LARGE" | "UNSUPPORTED_MEDIA_TYPE" | "UNPROCESSABLE_CONTENT" | "TOO_MANY_REQUESTS" | "CLIENT_CLOSED_REQUEST" | "INTERNAL_SERVER_ERROR" | "NOT_IMPLEMENTED" | "BAD_GATEWAY" | "SERVICE_UNAVAILABLE" | "GATEWAY_TIMEOUT" | "NETWORK_ERROR" | "CLIENT_ERROR" | "STREAM_INTERRUPTED" | (string & {}), unknown> & {
    ...;
}) | (TrpcError<...> & {
    ...;
}) | (TrpcError<...> & {
    ...;
}), {
    ...;
}, undefined>
create = 
createMutationController<{
    id: string;
    title: string;
    author: string | null;
    createdAt: string;
}, (TrpcError<"NOT_FOUND" | "BAD_REQUEST" | "UNAUTHORIZED" | "PARSE_ERROR" | "UNSUPPORTED_PROTOCOL" | "PAYMENT_REQUIRED" | "FORBIDDEN" | "METHOD_NOT_SUPPORTED" | "TIMEOUT" | "CONFLICT" | "PRECONDITION_FAILED" | "PAYLOAD_TOO_LARGE" | "UNSUPPORTED_MEDIA_TYPE" | "UNPROCESSABLE_CONTENT" | "TOO_MANY_REQUESTS" | "CLIENT_CLOSED_REQUEST" | "INTERNAL_SERVER_ERROR" | "NOT_IMPLEMENTED" | "BAD_GATEWAY" | "SERVICE_UNAVAILABLE" | "GATEWAY_TIMEOUT" | "NETWORK_ERROR" | "CLIENT_ERROR" | "STREAM_INTERRUPTED" | (string & {}), unknown> & {
    ...;
}) | (TrpcError<...> & {
    ...;
}) | (TrpcError<...> & {
    ...;
}), {
    ...;
}, undefined>(host: ReactiveControllerHost, options: Accessor<...>, queryClient?: QueryClient): MutationResultAccessor<...>
createMutationController(this, () =>
    this.
PostView.trpc: TrpcQueryUtilsFor<{
    post: {
        byId: BuildProcedure<InputDef<RootDef<Context, {}>, ZodObject<{
            id: ZodString;
        }, $strip>>, "query", {
            output: Post;
            errors: TrpcError<"NOT_FOUND", {
                id: string;
            }>;
            services: never;
            unmapped: never;
        }>;
        list: BuildProcedure<RootDef<Context, {}>, "query", {
            output: Post[];
            errors: never;
            services: never;
            unmapped: never;
        }>;
        create: BuildProcedure<InputDef<With<RootDef<Context, {}>, {
            ctx: Context;
            ctxAdded: {
                ...;
            };
            inputOut: Unset;
            errors: TrpcError<...>;
            shorts: never;
        }>, ZodObject<...>>, "mutation", {
            ...;
        }>;
    };
}, {}, {}>
trpc.
post: TrpcQueryUtils<ClientRouter<{
    byId: BuildProcedure<InputDef<RootDef<Context, {}>, ZodObject<{
        id: ZodString;
    }, $strip>>, "query", {
        output: Post;
        errors: TrpcError<"NOT_FOUND", {
            id: string;
        }>;
        services: never;
        unmapped: never;
    }>;
    list: BuildProcedure<RootDef<Context, {}>, "query", {
        output: Post[];
        errors: never;
        services: never;
        unmapped: never;
    }>;
    create: BuildProcedure<InputDef<With<RootDef<Context, {}>, {
        ctx: Context;
        ctxAdded: {
            ...;
        };
        inputOut: Unset;
        errors: TrpcError<...>;
        shorts: never;
    }>, ZodObject<...>>, "mutation", {
        ...;
    }>;
}, {}, undefined, {}>>
post.
create: MutationProcedureUtils<{
    ...;
}, {
    id: string;
    title: string;
    author: string | null;
    createdAt: string;
}, NonNullable<...>, Omit<...>>
create.
MutationProcedureUtils<{ title: string; }, { id: string; title: string; author: string | null; createdAt: string; }, NonNullable<UnexpectedError | (TrpcError<"UNAUTHORIZED", undefined> & { ...; }) | (TrpcError<...> & { ...; })>, Omit<...>>.mutationOptions<undefined>(opts?: (ContextBag<Omit<NonNullable<{
    signal?: AbortSignal | undefined;
} & BuiltinCallOptions>, "signal" | "lastEventId">> & MutationOptionsIn<{
    title: string;
}, {
    id: string;
    title: string;
    author: string | null;
    createdAt: string;
}, NonNullable<UnexpectedError | (TrpcError<"UNAUTHORIZED", undefined> & {
    readonly defined: true;
}) | (TrpcError<"BAD_REQUEST", InputValidationErrorData<{
    readonly code: "invalid_type";
    readonly expected: $ZodInvalidTypeExpected;
    readonly path: readonly [] | readonly [...];
    readonly message: string;
} | ... 10 more ... | {
    ...;
}>> & {
    ...;
})>, undefined>) | undefined): MutationOptionsOut<...>
mutationOptions(),
  );

  override PostView.render(): TemplateResult<1>render() {
    return const html: (strings: TemplateStringsArray, ...values: unknown[]) => TemplateResult<1>html`
      <h1>${this.
PostView.post: () => QueryObserverResult<{
    id: string;
    title: string;
    author: string | null;
    createdAt: string;
}, NonNullable<UnexpectedError | (TrpcError<"NOT_FOUND", {
    id: string;
}> & {
    readonly defined: true;
}) | (TrpcError<"BAD_REQUEST", InputValidationErrorData<{
    readonly code: "invalid_type";
    readonly expected: $ZodInvalidTypeExpected;
    readonly path: readonly [] | readonly ["id"];
    readonly message: string;
} | {
    readonly code: "too_big";
    readonly origin: "number" | "int" | "bigint" | "date" | "string" | "array" | "set" | "file" | (string & {});
    ... 4 more ...;
    readonly message: string;
} | ... 9 more ... | {
    ...;
}>> & {
    ...;
})>>
post().
data: {
    id: string;
    title: string;
    author: string | null;
    createdAt: string;
} | undefined
data?.title: string | undefinedtitle}</h1>
      <button @click=${() => this.
PostView.create: () => MutationObserverResult<{
    id: string;
    title: string;
    author: string | null;
    createdAt: string;
}, (TrpcError<"NOT_FOUND" | "BAD_REQUEST" | "UNAUTHORIZED" | "PARSE_ERROR" | "UNSUPPORTED_PROTOCOL" | "PAYMENT_REQUIRED" | "FORBIDDEN" | "METHOD_NOT_SUPPORTED" | "TIMEOUT" | "CONFLICT" | "PRECONDITION_FAILED" | "PAYLOAD_TOO_LARGE" | "UNSUPPORTED_MEDIA_TYPE" | "UNPROCESSABLE_CONTENT" | "TOO_MANY_REQUESTS" | "CLIENT_CLOSED_REQUEST" | "INTERNAL_SERVER_ERROR" | "NOT_IMPLEMENTED" | "BAD_GATEWAY" | "SERVICE_UNAVAILABLE" | "GATEWAY_TIMEOUT" | "NETWORK_ERROR" | "CLIENT_ERROR" | "STREAM_INTERRUPTED" | (string & {}), unknown> & {
    ...;
}) | (TrpcError<...> & {
    ...;
}) | (TrpcError<...> & {
    ...;
}), {
    ...;
}, undefined>
create().
MutationObserverBaseResult<TData = unknown, TError = Error, TVariables = void, TOnMutateResult = unknown>.mutate: (variables: {
    title: string;
}, options?: MutateOptions<{
    id: string;
    title: string;
    author: string | null;
    createdAt: string;
}, (TrpcError<"NOT_FOUND" | "BAD_REQUEST" | "UNAUTHORIZED" | "PARSE_ERROR" | "UNSUPPORTED_PROTOCOL" | "PAYMENT_REQUIRED" | "FORBIDDEN" | "METHOD_NOT_SUPPORTED" | "TIMEOUT" | "CONFLICT" | "PRECONDITION_FAILED" | "PAYLOAD_TOO_LARGE" | "UNSUPPORTED_MEDIA_TYPE" | "UNPROCESSABLE_CONTENT" | "TOO_MANY_REQUESTS" | "CLIENT_CLOSED_REQUEST" | "INTERNAL_SERVER_ERROR" | "NOT_IMPLEMENTED" | "BAD_GATEWAY" | "SERVICE_UNAVAILABLE" | "GATEWAY_TIMEOUT" | "NETWORK_ERROR" | "CLIENT_ERROR" | "STREAM_INTERRUPTED" | (string & {}), unknown> & {
    ...;
}) | (TrpcError<...> & {
    ...;
}) | (TrpcError<...> & {
    ...;
}), {
    title: string;
}, undefined> | undefined) => Promise<...>
mutate({ title: stringtitle: 'New' })}>
        New post
      </button>
    `;
  }
}
var customElements: CustomElementRegistrycustomElements.CustomElementRegistry.define(name: string, constructor: CustomElementConstructor, options?: ElementDefinitionOptions): voiddefine('post-view', class PostViewPostView);

Subscriptions

createSubscriptionController subscribes while the host is connected, and not during SSR. Call it (or read current) in render for status, data (the latest event) and error; it has reset(), and destroy() removes it from the host. Pass a function so the options are read again on each update, and a new input restarts the subscription:

class class TickerTicker extends class LitElementLitElement {
  static override 
Ticker.properties: {
    from: {};
}
properties = { from: {}from: {} };
  declare Ticker.from: numberfrom: number;

  
Ticker.trpc: TrpcQueryUtilsFor<{
    clock: {
        ticks: BuildProcedure<InputDef<RootDef<Context, {}>, z.ZodObject<{
            from: z.ZodNumber;
        }, z.core.$strip>>, "subscription", {
            output: number;
            errors: never;
            services: never;
        }>;
    };
}, {}, {}>
trpc = 
const useTrpc: (host: ReactiveElement) => TrpcQueryUtilsFor<{
    clock: {
        ticks: BuildProcedure<InputDef<RootDef<Context, {}>, z.ZodObject<{
            from: z.ZodNumber;
        }, z.core.$strip>>, "subscription", {
            output: number;
            errors: never;
            services: never;
        }>;
    };
}, {}, {}>
useTrpc(this);
  
Ticker.ticks: SubscriptionResultAccessor<number, NonNullable<UnexpectedError | (TrpcError<"BAD_REQUEST", InputValidationErrorData<{
    readonly code: "invalid_type";
    readonly expected: z.core.$ZodInvalidTypeExpected;
    readonly path: readonly [] | readonly ["from"];
    readonly message: string;
} | {
    readonly code: "too_big";
    readonly origin: "number" | "int" | "bigint" | "date" | "string" | "array" | "set" | "file" | (string & {});
    readonly maximum: string | number;
    readonly inclusive?: boolean | undefined;
    readonly exact?: boolean | undefined;
    readonly path: readonly [] | readonly ["from"];
    readonly message: string;
} | {
    readonly code: "too_small";
    ... 5 more ...;
    readonly message: string;
} | ... 8 more ... | {
    ...;
}>> & {
    ...;
})>>
ticks = 
createSubscriptionController<number, NonNullable<UnexpectedError | (TrpcError<"BAD_REQUEST", InputValidationErrorData<{
    readonly code: "invalid_type";
    readonly expected: z.core.$ZodInvalidTypeExpected;
    readonly path: readonly [] | readonly ["from"];
    readonly message: string;
} | {
    readonly code: "too_big";
    readonly origin: "number" | "int" | "bigint" | "date" | "string" | "array" | "set" | "file" | (string & {});
    readonly maximum: string | number;
    readonly inclusive?: boolean | undefined;
    readonly exact?: boolean | undefined;
    readonly path: readonly [] | readonly ["from"];
    readonly message: string;
} | {
    readonly code: "too_small";
    ... 5 more ...;
    readonly message: string;
} | ... 8 more ... | {
    ...;
}>> & {
    ...;
})>>(host: ReactiveControllerHost, options: OptionsOrFn<...>): SubscriptionResultAccessor<...>
createSubscriptionController(this, () =>
    this.
Ticker.trpc: TrpcQueryUtilsFor<{
    clock: {
        ticks: BuildProcedure<InputDef<RootDef<Context, {}>, z.ZodObject<{
            from: z.ZodNumber;
        }, z.core.$strip>>, "subscription", {
            output: number;
            errors: never;
            services: never;
        }>;
    };
}, {}, {}>
trpc.
clock: TrpcQueryUtils<ClientRouter<{
    ticks: BuildProcedure<InputDef<RootDef<Context, {}>, z.ZodObject<{
        from: z.ZodNumber;
    }, z.core.$strip>>, "subscription", {
        output: number;
        errors: never;
        services: never;
    }>;
}, {}, undefined, {}>>
clock.
ticks: SubscriptionProcedureUtils<{
    from: number;
}, number, NonNullable<UnexpectedError | (TrpcError<"BAD_REQUEST", InputValidationErrorData<{
    readonly code: "invalid_type";
    readonly expected: z.core.$ZodInvalidTypeExpected;
    readonly path: readonly [] | readonly ["from"];
    readonly message: string;
} | {
    readonly code: "too_big";
    readonly origin: "number" | "int" | "bigint" | "date" | "string" | "array" | "set" | "file" | (string & {});
    readonly maximum: string | number;
    readonly inclusive?: boolean | undefined;
    readonly exact?: boolean | undefined;
    readonly path: readonly [] | readonly ["from"];
    readonly message: string;
} | {
    readonly code: "too_small";
    ... 5 more ...;
    readonly message: string;
} | ... 8 more ... | {
    ...;
}>> & {
    ...;
})>, Omit<...>>
ticks.
SubscriptionProcedureUtils<{ from: number; }, number, NonNullable<UnexpectedError | (TrpcError<"BAD_REQUEST", InputValidationErrorData<{ readonly code: "invalid_type"; readonly expected: $ZodInvalidTypeExpected; readonly path: readonly [] | readonly [...]; readonly message: string; } | ... 10 more ... | { ...; }>> & { ...; })>, Omit<...>>.subscriptionOptions(opts: {
    input: {
        from: number;
    } | unique symbol;
} & ContextBag<Omit<NonNullable<{
    signal?: AbortSignal | undefined;
} & BuiltinCallOptions & {
    lastEventId?: string | undefined;
}>, "signal" | "lastEventId">> & {
    enabled?: boolean | undefined;
} & SubscriptionCallbacks<number, NonNullable<UnexpectedError | (TrpcError<"BAD_REQUEST", InputValidationErrorData<{
    readonly code: "invalid_type";
    readonly expected: z.core.$ZodInvalidTypeExpected;
    readonly path: readonly [] | readonly ["from"];
    readonly message: string;
} | ... 10 more ... | {
    ...;
}>> & {
    ...;
})>>): TrpcSubscriptionOptions<...>
subscriptionOptions({ 
input: {
    from: number;
} | unique symbol
input: { from: numberfrom: this.Ticker.from: numberfrom } }),
  );

  override Ticker.render(): TemplateResult<1>render() {
    return const html: (strings: TemplateStringsArray, ...values: unknown[]) => TemplateResult<1>html`<p>${this.
Ticker.ticks: () => SubscriptionResult<number, NonNullable<UnexpectedError | (TrpcError<"BAD_REQUEST", InputValidationErrorData<{
    readonly code: "invalid_type";
    readonly expected: z.core.$ZodInvalidTypeExpected;
    readonly path: readonly [] | readonly ["from"];
    readonly message: string;
} | {
    readonly code: "too_big";
    readonly origin: "number" | "int" | "bigint" | "date" | "string" | "array" | "set" | "file" | (string & {});
    readonly maximum: string | number;
    readonly inclusive?: boolean | undefined;
    readonly exact?: boolean | undefined;
    readonly path: readonly [] | readonly ["from"];
    readonly message: string;
} | {
    readonly code: "too_small";
    ... 5 more ...;
    readonly message: string;
} | ... 8 more ... | {
    ...;
}>> & {
    ...;
})>>
ticks().data: number | undefineddata}</p>`;
  }
}

What subscriptions share, and the query-cache forms (liveOptions(), streamedOptions()), are in Subscriptions.