feat: add server property when load executes on server

.changeset/fresh-pugs-yell.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': minor
+---
+
+feat: add server property when load executes on server

documentation/docs/20-core-concepts/20-load.md

@@ -202,6 +202,8 @@ Server `load` functions are called with a `ServerLoadEvent`, which inherits `cli
 
 Universal `load` functions are called with a `LoadEvent`, which has a `data` property. If you have `load` functions in both `+page.js` and `+page.server.js` (or `+layout.js` and `+layout.server.js`), the return value of the server `load` function is the `data` property of the universal `load` function's argument.
 
+> [!NOTE] Since 2.??, when universal `load` functions are called on server, `LoadEvent` includes `server` object, which consists of `clientAddress`, `cookies`, `locals`, `platform` and `request`. `server` becomes `undefined` if `load` functions are called on client.
+
 ### Output
 
 A universal `load` function can return an object containing any values, including things like custom classes and component constructors.

packages/kit/src/exports/public.d.ts

@@ -1143,6 +1143,14 @@ export interface LoadEvent<
 		/** The span associated with the current `load` function. */
 		current: Span;
 	};
+
+	/**
+	 * Server only properties when `LoadEvent` executed on server.
+	 */
+	server?: Omit<
+		ServerLoadEvent<Params, ParentData, RouteId>,
+		keyof LoadEvent<Params, Data, ParentData, RouteId>
+	>;
 }
 
 export interface NavigationEvent<

packages/kit/src/runtime/server/page/load_data.js

@@ -244,7 +244,17 @@ export async function load_data({
 					depends: () => {},
 					parent,
 					untrack: (fn) => fn(),
-					tracing: traced_event.tracing
+					tracing: traced_event.tracing,
+					server: {
+						cookies: event.cookies,
+						getClientAddress: event.getClientAddress,
+						locals: event.locals,
+						platform: event.platform,
+						request: event.request,
+						isDataRequest: event.isDataRequest,
+						isSubRequest: event.isSubRequest,
+						isRemoteRequest: event.isRemoteRequest
+					}
 				})
 			);
 		}

packages/kit/test/apps/basics/src/routes/load/universal-load/csr/+page.js

@@ -0,0 +1,8 @@
+import { browser } from '$app/environment';
+
+/** @type {import('@sveltejs/kit').Load} */
+export async function load({ server }) {
+	return {
+		correct: browser === !server && (!server || ((await server.request.arrayBuffer()) && true))
+	};
+}

packages/kit/test/apps/basics/src/routes/load/universal-load/csr/+page.svelte

@@ -0,0 +1,6 @@
+<script>
+	/** @type {import('./$types').PageData} */
+	export let data;
+</script>
+
+<h1>Is it correct? {data.correct}</h1>

packages/kit/test/apps/basics/src/routes/load/universal-load/ssr/+page.js

@@ -0,0 +1,8 @@
+import { browser } from '$app/environment';
+
+/** @type {import('@sveltejs/kit').Load} */
+export async function load({ server }) {
+	return {
+		correct: browser === !server && (!server || ((await server.request.arrayBuffer()) && true))
+	};
+}

packages/kit/test/apps/basics/src/routes/load/universal-load/ssr/+page.svelte

@@ -0,0 +1,6 @@
+<script>
+	/** @type {import('./$types').PageData} */
+	export let data;
+</script>
+
+<h1>Is it correct? {data.correct}</h1>

packages/kit/types/index.d.ts

@@ -1119,6 +1119,14 @@ declare module '@sveltejs/kit' {
 			/** The span associated with the current `load` function. */
 			current: Span;
 		};
+
+		/**
+		 * Server only properties when `LoadEvent` executed on server.
+		 */
+		server?: Omit<
+			ServerLoadEvent<Params, ParentData, RouteId>,
+			keyof LoadEvent<Params, Data, ParentData, RouteId>
+		>;
 	}
 
 	export interface NavigationEvent<