[feat] add App.PageData type (#6226)

Closes #5951

Author: dummdidumm

.changeset/loud-peaches-enjoy.md

@@ -0,0 +1,6 @@
+---
+'create-svelte': patch
+'@sveltejs/kit': patch
+---
+
+[feat] add App.PageData type

packages/create-svelte/templates/default/src/app.d.ts

@@ -6,6 +6,8 @@ declare namespace App {
 		userid: string;
 	}
 
+	// interface PageData {}
+
 	// interface Platform {}
 
 	// interface PrivateEnv {}

packages/create-svelte/templates/libskeleton/src/app.d.ts

@@ -5,6 +5,7 @@
 // and what to do when importing types
 declare namespace App {
 	// interface Locals {}
+	// interface PageData {}
 	// interface Platform {}
 	// interface PrivateEnv {}
 	// interface PublicEnv {}

packages/create-svelte/templates/skeleton/src/app.d.ts

@@ -3,6 +3,7 @@
 // and what to do when importing types
 declare namespace App {
 	// interface Locals {}
+	// interface PageData {}
 	// interface Platform {}
 	// interface PrivateEnv {}
 	// interface PublicEnv {}

packages/kit/src/core/sync/create_manifest_data/index.js

@@ -180,7 +180,7 @@ function create_routes_and_nodes(cwd, config, fallback) {
 							component: project_relative
 						};
 					} else if (item.is_layout) {
-						if (!route.layout) route.layout = { depth };
+						if (!route.layout) route.layout = { depth, child_pages: [] };
 						route.layout.component = project_relative;
 						if (item.uses_layout !== undefined) route.layout.parent_id = item.uses_layout;
 					} else {
@@ -189,7 +189,7 @@ function create_routes_and_nodes(cwd, config, fallback) {
 						if (item.uses_layout !== undefined) route.leaf.parent_id = item.uses_layout;
 					}
 				} else if (item.is_layout) {
-					if (!route.layout) route.layout = { depth };
+					if (!route.layout) route.layout = { depth, child_pages: [] };
 					route.layout[item.kind] = project_relative;
 				} else if (item.is_page) {
 					if (!route.leaf) route.leaf = { depth };
@@ -223,7 +223,7 @@ function create_routes_and_nodes(cwd, config, fallback) {
 		}
 
 		if (!root.layout?.component) {
-			if (!root.layout) root.layout = { depth: 0 };
+			if (!root.layout) root.layout = { depth: 0, child_pages: [] };
 			root.layout.component = posixify(path.relative(cwd, `${fallback}/layout.svelte`));
 		}
 
@@ -290,6 +290,9 @@ function create_routes_and_nodes(cwd, config, fallback) {
 					}
 
 					if (current_route.layout) {
+						/** @type {import('types').PageNode[]} */ (current_route.layout.child_pages).push(
+							route.leaf
+						);
 						current_node.parent = current_node = current_route.layout;
 						parent_id = current_node.parent_id;
 					} else {

packages/kit/src/core/sync/sync.js

@@ -4,7 +4,7 @@ import { write_client_manifest } from './write_client_manifest.js';
 import { write_matchers } from './write_matchers.js';
 import { write_root } from './write_root.js';
 import { write_tsconfig } from './write_tsconfig.js';
-import { write_types, write_all_types } from './write_types.js';
+import { write_types, write_all_types } from './write_types/index.js';
 import { write_ambient } from './write_ambient.js';
 
 /**