export ValidationError interface (#6885)

* export ValidationError interface

* add symbol to ValidationError

* Update packages/kit/types/index.d.ts

* fucking whitespace

* unique interface

* only include exported declarations in docs

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
Co-authored-by: Rich Harris <hello@rich-harris.dev>

packages/kit/scripts/extract-types.js

@@ -22,6 +22,11 @@ function get_types(code, statements) {
 
 	if (statements) {
 		for (const statement of statements) {
+			const modifiers = ts.canHaveModifiers(statement) ? ts.getModifiers(statement) : undefined;
+
+			const export_modifier = modifiers?.find((modifier) => modifier.kind === 93);
+			if (!export_modifier) continue;
+
 			if (
 				ts.isClassDeclaration(statement) ||
 				ts.isInterfaceDeclaration(statement) ||

packages/kit/types/index.d.ts

@@ -13,7 +13,8 @@ import {
 	PrerenderOnErrorValue,
 	RequestOptions,
 	RouteDefinition,
-	TrailingSlash
+	TrailingSlash,
+	UniqueInterface
 } from './private.js';
 import { SSRNodeLoader, SSRRoute, ValidatedConfig } from './internal.js';
 import { HttpError, Redirect } from '../src/runtime/control.js';
@@ -52,7 +53,8 @@ type OptionalUnion<
 > = U extends unknown ? { [P in Exclude<A, keyof U>]?: never } & U : never;
 
 // Needs to be here, else ActionData will be resolved to unknown - probably because of "d.ts file imports .js file" in combination with allowJs
-interface ValidationError<T extends Record<string, unknown> | undefined = undefined> {
+export interface ValidationError<T extends Record<string, unknown> | undefined = undefined>
+	extends UniqueInterface {
 	status: number;
 	data: T;
 }

packages/kit/types/private.d.ts

@@ -207,3 +207,12 @@ export interface RouteSegment {
 }
 
 export type TrailingSlash = 'never' | 'always' | 'ignore';
+
+/**
+ * This doesn't actually exist, it's a way to better distinguish the type
+ */
+declare const uniqueSymbol: unique symbol;
+
+export interface UniqueInterface {
+	readonly [uniqueSymbol]: unknown;
+}