fix: export temporary LegacyComponentType (#14256) (#14257)

closes  #14256

helps TypeScript when generating dts files to not fail

.changeset/lovely-mayflies-sing.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: provide temporary `LegacyComponentType`

packages/svelte/src/ambient.d.ts

@@ -1,17 +1,9 @@
 declare module '*.svelte' {
 	// use prettier-ignore for a while because of https://github.com/sveltejs/language-tools/commit/026111228b5814a9109cc4d779d37fb02955fb8b
 	// prettier-ignore
-	import { SvelteComponent, Component, type ComponentConstructorOptions } from 'svelte'
+	import { SvelteComponent } from 'svelte'
-
+	import { LegacyComponentType } from 'svelte/legacy';
-	// Support using the component as both a class and function during the transition period
+	const Comp: LegacyComponentType;
-	// prettier-ignore
-	interface ComponentType {
-		(
-			...args: Parameters<Component<Record<string, any>>>
-		): ReturnType<Component<Record<string, any>, Record<string, any>>>
-		new (o: ComponentConstructorOptions): SvelteComponent
-	}
-	const Comp: ComponentType;
 	type Comp = SvelteComponent;
 	export default Comp;
 }

packages/svelte/src/legacy/legacy-client.js

@@ -63,6 +63,11 @@ export function asClassComponent(component) {
 	};
 }
 
+/**
+ * Support using the component as both a class and function during the transition period
+ * @typedef  {{new (o: ComponentConstructorOptions): SvelteComponent;(...args: Parameters<Component<Record<string, any>>>): ReturnType<Component<Record<string, any>, Record<string, any>>>;}} LegacyComponentType
+ */
+
 class Svelte4Component {
 	/** @type {any} */
 	#events;

packages/svelte/types/index.d.ts

@@ -1578,6 +1578,13 @@ declare module 'svelte/legacy' {
 	 * @deprecated Use this only as a temporary solution to migrate your automatically delegated events in Svelte 5.
 	 */
 	export function createBubbler(): (type: string) => (event: Event) => boolean;
+	/**
+	 * Support using the component as both a class and function during the transition period
+	 */
+	export type LegacyComponentType = {
+		new (o: ComponentConstructorOptions): SvelteComponent;
+		(...args: Parameters<Component<Record<string, any>>>): ReturnType<Component<Record<string, any>, Record<string, any>>>;
+	};
 	/**
 	 * Substitute for the `trusted` event modifier
 	 * @deprecated
@@ -2308,17 +2315,9 @@ declare module 'svelte/types/compiler/interfaces' {
 }declare module '*.svelte' {
 	// use prettier-ignore for a while because of https://github.com/sveltejs/language-tools/commit/026111228b5814a9109cc4d779d37fb02955fb8b
 	// prettier-ignore
-	import { SvelteComponent, Component, type ComponentConstructorOptions } from 'svelte'
+	import { SvelteComponent } from 'svelte'
-
+	import { LegacyComponentType } from 'svelte/legacy';
-	// Support using the component as both a class and function during the transition period
+	const Comp: LegacyComponentType;
-	// prettier-ignore
-	interface ComponentType {
-		(
-			...args: Parameters<Component<Record<string, any>>>
-		): ReturnType<Component<Record<string, any>, Record<string, any>>>
-		new (o: ComponentConstructorOptions): SvelteComponent
-	}
-	const Comp: ComponentType;
 	type Comp = SvelteComponent;
 	export default Comp;
 }