feat: Merge ErrorLoad and Load, make Input and Output typings public

.changeset/moody-rabbits-complain.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+Made LoadInput and LoadOutput types public, merged ErrorLoad and Load declarations

documentation/docs/03-loading.md

@@ -50,7 +50,7 @@ It is recommended that you not store pre-request state in global variables, but
 
 ### Input
 
-The `load` function receives an object containing six fields — `url`, `params`, `props`, `fetch`, `session` and `stuff`. The `load` function is reactive, and will re-run when its parameters change, but only if they are used in the function. Specifically, if `url`, `session` or `stuff` are used in the function, they will be re-run whenever their value changes, and likewise for the individual properties of `params`.
+The `load` function receives an object containing eight fields — `url`, `params`, `props`, `fetch`, `session`, `stuff`, `status`, and `error`. The `load` function is reactive, and will re-run when its parameters change, but only if they are used in the function. Specifically, if `url`, `session` or `stuff` are used in the function, they will be re-run whenever their value changes, and likewise for the individual properties of `params`.
 
 > Note that destructuring parameters in the function declaration is enough to count as using them.
 
@@ -93,6 +93,14 @@ If the page you're loading has an endpoint, the data returned from it is accessi
 
 `stuff` is passed from layouts to descendant layouts and pages, and can be filled with anything else you need to make available. For the root `__layout.svelte` component, it is equal to `{}`, but if that component's `load` function returns an object with a `stuff` property, it will be available to subsequent `load` functions.
 
+#### status
+
+`status` is the HTTP status code when rendering an error page, or `null` otherwise.
+
+#### error
+
+`error` is the error that was thrown (or returned from a previous `load`) when rendering an error page, or `null` otherwise.
+
 ### Output
 
 If you return a Promise from `load`, SvelteKit will delay rendering until the promise resolves. The return value has several properties, all optional:

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

@@ -497,7 +497,7 @@ export function create_client({ target, session, base, trailing_slash }) {
 		const session = $session;
 
 		if (module.load) {
-			/** @type {import('types').LoadInput | import('types').ErrorLoadInput} */
+			/** @type {import('types').LoadInput} */
 			const load_input = {
 				routeId,
 				params: uses_params,
@@ -520,7 +520,9 @@ export function create_client({ target, session, base, trailing_slash }) {
 					node.uses.dependencies.add(href);
 
 					return started ? fetch(resource, info) : initial_fetch(resource, info);
-				}
+				},
+				status: status ?? null,
+				error: error ?? null
 			};
 
 			if (import.meta.env.DEV) {
@@ -532,11 +534,6 @@ export function create_client({ target, session, base, trailing_slash }) {
 				});
 			}
 
-			if (error) {
-				/** @type {import('types').ErrorLoadInput} */ (load_input).status = status;
-				/** @type {import('types').ErrorLoadInput} */ (load_input).error = error;
-			}
-
 			const loaded = await module.load.call(null, load_input);
 
 			if (!loaded) {

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

@@ -74,7 +74,7 @@ export async function load_node({
 			redirect: shadow.redirect
 		};
 	} else if (module.load) {
-		/** @type {import('types').LoadInput | import('types').ErrorLoadInput} */
+		/** @type {import('types').LoadInput} */
 		const load_input = {
 			url: state.prerender ? create_prerendering_url_proxy(event.url) : event.url,
 			params: event.params,
@@ -308,7 +308,9 @@ export async function load_node({
 
 				return proxy;
 			},
-			stuff: { ...stuff }
+			stuff: { ...stuff },
+			status: is_error ? status ?? null : null,
+			error: is_error ? error ?? null : null
 		};
 
 		if (options.dev) {
@@ -320,11 +322,6 @@ export async function load_node({
 			});
 		}
 
-		if (is_error) {
-			/** @type {import('types').ErrorLoadInput} */ (load_input).status = status;
-			/** @type {import('types').ErrorLoadInput} */ (load_input).error = error;
-		}
-
 		loaded = await module.load.call(null, load_input);
 
 		if (!loaded) {

packages/kit/test/apps/basics/src/routes/errors/nested-error-page/__error.svelte

@@ -1,5 +1,5 @@
 <script context="module">
-	/** @type {import('@sveltejs/kit').ErrorLoad} */
+	/** @type {import('@sveltejs/kit').Load} */
 	export async function load({ status, error }) {
 		return {
 			props: {

packages/kit/test/apps/basics/src/routes/nested-layout/foo/bar/__error.svelte

@@ -1,5 +1,5 @@
 <script context="module">
-	/** @type {import('@sveltejs/kit').ErrorLoad} */
+	/** @type {import('@sveltejs/kit').Load} */
 	export async function load({ status, error }) {
 		return {
 			props: {

packages/kit/test/apps/basics/src/routes/store/stuff/__error.svelte

@@ -1,5 +1,5 @@
 <script context="module">
-	/** @type {import('@sveltejs/kit').ErrorLoad} */
+	/** @type {import('@sveltejs/kit').Load} */
 	export function load({ error }) {
 		return {
 			stuff: {

packages/kit/types/index.d.ts

@@ -7,10 +7,7 @@ import { CompileOptions } from 'svelte/types/compiler/interfaces';
 import {
 	AdapterEntry,
 	CspDirectives,
-	ErrorLoadInput,
 	JSONValue,
-	LoadInput,
-	LoadOutput,
 	Logger,
 	MaybePromise,
 	Prerendered,
@@ -157,13 +154,6 @@ export interface Config {
 	preprocess?: any;
 }
 
-export interface ErrorLoad<
-	Params extends Record<string, string> = Record<string, string>,
-	Props extends Record<string, any> = Record<string, any>
-> {
-	(input: ErrorLoadInput<Params>): MaybePromise<LoadOutput<Props>>;
-}
-
 export interface ExternalFetch {
 	(req: Request): Promise<Response>;
 }
@@ -196,6 +186,30 @@ export interface Load<
 	(input: LoadInput<Params, InputProps>): MaybePromise<LoadOutput<OutputProps>>;
 }
 
+export interface LoadInput<
+	Params extends Record<string, string> = Record<string, string>,
+	Props extends Record<string, any> = Record<string, any>
+> {
+	fetch(info: RequestInfo, init?: RequestInit): Promise<Response>;
+	params: Params;
+	props: Props;
+	routeId: string | null;
+	session: App.Session;
+	stuff: Partial<App.Stuff>;
+	url: URL;
+	status: number | null;
+	error: Error | null;
+}
+
+export interface LoadOutput<Props extends Record<string, any> = Record<string, any>> {
+	status?: number;
+	error?: string | Error;
+	redirect?: string;
+	props?: Props;
+	stuff?: Partial<App.Stuff>;
+	maxage?: number;
+}
+
 export interface Navigation {
 	from: URL;
 	to: URL;

packages/kit/types/private.d.ts

@@ -134,12 +134,6 @@ export interface CspDirectives {
 	>;
 }
 
-export interface ErrorLoadInput<Params extends Record<string, string> = Record<string, string>>
-	extends LoadInput<Params> {
-	status?: number;
-	error?: Error;
-}
-
 export type HttpMethod = 'get' | 'head' | 'post' | 'put' | 'delete' | 'patch';
 
 export interface JSONObject {
@@ -156,28 +150,6 @@ export type JSONValue =
 	| JSONValue[]
 	| JSONObject;
 
-export interface LoadInput<
-	Params extends Record<string, string> = Record<string, string>,
-	Props extends Record<string, any> = Record<string, any>
-> {
-	fetch(info: RequestInfo, init?: RequestInit): Promise<Response>;
-	params: Params;
-	props: Props;
-	routeId: string | null;
-	session: App.Session;
-	stuff: Partial<App.Stuff>;
-	url: URL;
-}
-
-export interface LoadOutput<Props extends Record<string, any> = Record<string, any>> {
-	status?: number;
-	error?: string | Error;
-	redirect?: string;
-	props?: Props;
-	stuff?: Partial<App.Stuff>;
-	maxage?: number;
-}
-
 export interface Logger {
 	(msg: string): void;
 	success(msg: string): void;