feat: add universal IDs to client nodes

Author: elliott-with-the-longest-name-on-github

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

@@ -29,6 +29,11 @@ export function write_client_manifest(kit, manifest_data, output, metadata) {
 			);
 		}
 
+		if (kit.tracing === 'client' || kit.tracing === true) {
+			// we don't need to include these if tracing is disabled -- they make the manifest bigger
+			declarations.push(`export const universal_id = ${s(node.universal)};`);
+		}
+
 		if (node.component) {
 			declarations.push(
 				`export { default as component } from ${s(

packages/kit/src/runtime/client/client.js

@@ -36,7 +36,12 @@ import {
 import { validate_page_exports } from '../../utils/exports.js';
 import { compact } from '../../utils/array.js';
 import { HttpError, Redirect, SvelteKitError } from '../control.js';
-import { INVALIDATED_PARAM, TRAILING_SLASH_PARAM, validate_depends } from '../shared.js';
+import {
+	INVALIDATED_PARAM,
+	TRAILING_SLASH_PARAM,
+	validate_depends,
+	validate_load_response
+} from '../shared.js';
 import { get_message, get_status } from '../../utils/error.js';
 import { writable } from 'svelte/store';
 import { page, update, navigating } from './state.svelte.js';
@@ -776,19 +781,11 @@ async function load_node({ loader, parent, url, params, route, server_data_node
 				lock_fetch();
 				data = await traced_load();
 
-				if (data != null && Object.getPrototypeOf(data) !== Object.prototype) {
-					throw new Error(
-						`the load function located in ${node.universal_id} returned ${
-							typeof data !== 'object'
-								? `a ${typeof data}`
-								: data instanceof Response
-									? 'a Response object'
-									: Array.isArray(data)
-										? 'an array'
-										: 'a non-plain object'
-						}, but must return a plain object at the top level (i.e. \`return {...}\`)`
-					);
-				}
+				validate_load_response(
+					data,
+					// universal_id isn't populated if tracing is disabled because it adds otherwise unnecessary bloat to the manifest
+					node.universal_id ? `in ${node.universal_id}` : `related to route '${route.id}'`
+				);
 			} finally {
 				unlock_fetch();
 			}

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

@@ -1,6 +1,6 @@
 import { DEV } from 'esm-env';
 import { disable_search, make_trackable } from '../../../utils/url.js';
-import { validate_depends } from '../../shared.js';
+import { validate_depends, validate_load_response } from '../../shared.js';
 import { b64_encode } from '../../utils.js';
 import { with_event } from '../../app/server/event.js';
 import { record_span } from '../../telemetry/record_span.js';
@@ -176,7 +176,7 @@ export async function load_server_data({ event, state, node, parent, tracing })
 	});
 
 	if (__SVELTEKIT_DEV__) {
-		validate_load_response(result, node.server_id);
+		validate_load_response(result, `in ${node.server_id}`);
 	}
 
 	done = true;
@@ -252,7 +252,7 @@ export async function load_data({
 	});
 
 	if (__SVELTEKIT_DEV__) {
-		validate_load_response(result, node.universal_id);
+		validate_load_response(result, `in ${node.universal_id}`);
 	}
 
 	return result ?? null;
@@ -436,23 +436,3 @@ async function stream_to_string(stream) {
 	}
 	return result;
 }
-
-/**
- * @param {any} data
- * @param {string} [id]
- */
-function validate_load_response(data, id) {
-	if (data != null && Object.getPrototypeOf(data) !== Object.prototype) {
-		throw new Error(
-			`a load function in ${id} returned ${
-				typeof data !== 'object'
-					? `a ${typeof data}`
-					: data instanceof Response
-						? 'a Response object'
-						: Array.isArray(data)
-							? 'an array'
-							: 'a non-plain object'
-			}, but must return a plain object at the top level (i.e. \`return {...}\`)`
-		);
-	}
-}

packages/kit/src/runtime/shared.js

@@ -14,3 +14,23 @@ export function validate_depends(route_id, dep) {
 export const INVALIDATED_PARAM = 'x-sveltekit-invalidated';
 
 export const TRAILING_SLASH_PARAM = 'x-sveltekit-trailing-slash';
+
+/**
+ * @param {any} data
+ * @param {string} [location_description]
+ */
+export function validate_load_response(data, location_description) {
+	if (data != null && Object.getPrototypeOf(data) !== Object.prototype) {
+		throw new Error(
+			`a load function ${location_description} returned ${
+				typeof data !== 'object'
+					? `a ${typeof data}`
+					: data instanceof Response
+						? 'a Response object'
+						: Array.isArray(data)
+							? 'an array'
+							: 'a non-plain object'
+			}, but must return a plain object at the top level (i.e. \`return {...}\`)`
+		);
+	}
+}

packages/kit/src/types/internal.d.ts

@@ -111,6 +111,7 @@ export interface CSRPageNode {
 		load?: Load;
 		trailingSlash?: TrailingSlash;
 	};
+	universal_id?: string;
 }
 
 export type CSRPageNodeLoader = () => Promise<CSRPageNode>;