breaking: remove resolvePath (#11265)

closes #10282

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>
Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>

Author: Rich-Harris

.changeset/eighty-scissors-kick.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': major
+---
+
+breaking: remove `resolvePath` in favour of `resolveRoute` from `$app/paths`

documentation/docs/60-appendix/30-migrating-to-sveltekit-2.md

@@ -92,6 +92,23 @@ This inconsistency is fixed in version 2. Paths are either always relative or al
 
 Previously it was possible to track URLs from `fetch`es on the server in order to rerun load functions. This poses a possible security risk (private URLs leaking), and as such it was behind the `dangerZone.trackServerFetches` setting, which is now removed.
 
+## `resolvePath` has been removed
+
+SvelteKit 1 included a function called `resolvePath` which allows you to resolve a route ID (like `/blog/[slug]`) and a set of parameters (like `{ slug: 'hello' }`) to a pathname. Unfortunately the return value didn't include the `base` path, limiting its usefulness in cases where `base` was set.
+
+As such, SvelteKit 2 replaces `resolvePath` with a (slightly better named) function called `resolveRoute`, which is imported from `$app/paths` and which takes `base` into account.
+
+```diff
+-import { resolvePath } from '@sveltejs/kit';
+-import { base } from '$app/paths';
++import { resolveRoute } from '$app/paths';
+
+-const path = base + resolvePath('/blog/[slug]', { slug });
++const path = resolveRoute('/blog/[slug]', { slug });
+```
+
+`svelte-migrate` will do the method replacement for you, though if you later prepend the result with `base`, you need to remove that yourself.
+
 ## Updated dependency requirements
 
 SvelteKit requires Node `18.13` or higher, Vite `^5.0`, vite-plugin-svelte `^3.0`, TypeScript `^5.0` and Svelte version 4 or higher. `svelte-migrate` will do the `package.json` bumps for you.

packages/kit/src/core/postbuild/analyse.js

@@ -11,9 +11,9 @@ import {
 import { load_config } from '../config/index.js';
 import { forked } from '../../utils/fork.js';
 import { installPolyfills } from '../../exports/node/polyfills.js';
-import { resolvePath } from '../../exports/index.js';
 import { ENDPOINT_METHODS } from '../../constants.js';
 import { filter_private_env, filter_public_env } from '../../utils/env.js';
+import { resolve_route } from '../../utils/routing.js';
 
 export default forked(import.meta.url, analyse);
 
@@ -101,7 +101,7 @@ async function analyse({ manifest_path, env }) {
 			},
 			prerender: page?.prerender ?? endpoint?.prerender,
 			entries:
-				entries && (await entries()).map((entry_object) => resolvePath(route.id, entry_object))
+				entries && (await entries()).map((entry_object) => resolve_route(route.id, entry_object))
 		});
 	}
 

packages/kit/src/exports/index.js

@@ -1,6 +1,5 @@
 import { HttpError, Redirect, ActionFailure } from '../runtime/control.js';
 import { BROWSER, DEV } from 'esm-env';
-import { get_route_segments } from '../utils/routing.js';
 
 export { VERSION } from '../version.js';
 
@@ -183,58 +182,3 @@ export function fail(status, data) {
 	// @ts-expect-error unique symbol missing
 	return new ActionFailure(status, data);
 }
-
-const basic_param_pattern = /\[(\[)?(\.\.\.)?(\w+?)(?:=(\w+))?\]\]?/g;
-
-let warned = false;
-
-/**
- * @deprecated Use `resolveRoute` from `$app/paths` instead.
- *
- * Populate a route ID with params to resolve a pathname.
- * @example
- * ```js
- * resolvePath(
- *   `/blog/[slug]/[...somethingElse]`,
- *   {
- *     slug: 'hello-world',
- *     somethingElse: 'something/else'
- *   }
- * ); // `/blog/hello-world/something/else`
- * ```
- * @param {string} id
- * @param {Record<string, string | undefined>} params
- * @returns {string}
- */
-export function resolvePath(id, params) {
-	if (!warned) {
-		console.warn('`resolvePath` is deprecated. Use `resolveRoute` from `$app/paths` instead.');
-		warned = true;
-	}
-
-	const segments = get_route_segments(id);
-	return (
-		'/' +
-		segments
-			.map((segment) =>
-				segment.replace(basic_param_pattern, (_, optional, rest, name) => {
-					const param_value = params[name];
-
-					// This is nested so TS correctly narrows the type
-					if (!param_value) {
-						if (optional) return '';
-						if (rest && param_value !== undefined) return '';
-						throw new Error(`Missing parameter '${name}' in route ${id}`);
-					}
-
-					if (param_value.startsWith('/') || param_value.endsWith('/'))
-						throw new Error(
-							`Parameter '${name}' in route ${id} cannot start or end with a slash -- this would cause an invalid route like foo//bar`
-						);
-					return param_value;
-				})
-			)
-			.filter(Boolean)
-			.join('/')
-	);
-}

packages/kit/src/exports/index.spec.js

@@ -1,8 +1,6 @@
 export { base, assets } from '__sveltekit/paths';
 import { base } from '__sveltekit/paths';
-import { get_route_segments } from '../../utils/routing.js';
-
-const basic_param_pattern = /\[(\[)?(\.\.\.)?(\w+?)(?:=(\w+))?\]\]?/g;
+import { resolve_route } from '../../utils/routing.js';
 
 /**
  * Populate a route ID with params to resolve a pathname.
@@ -21,30 +19,5 @@ const basic_param_pattern = /\[(\[)?(\.\.\.)?(\w+?)(?:=(\w+))?\]\]?/g;
  * @returns {string}
  */
 export function resolveRoute(id, params) {
-	const segments = get_route_segments(id);
-	return (
-		base +
-		'/' +
-		segments
-			.map((segment) =>
-				segment.replace(basic_param_pattern, (_, optional, rest, name) => {
-					const param_value = params[name];
-
-					// This is nested so TS correctly narrows the type
-					if (!param_value) {
-						if (optional) return '';
-						if (rest && param_value !== undefined) return '';
-						throw new Error(`Missing parameter '${name}' in route ${id}`);
-					}
-
-					if (param_value.startsWith('/') || param_value.endsWith('/'))
-						throw new Error(
-							`Parameter '${name}' in route ${id} cannot start or end with a slash -- this would cause an invalid route like foo//bar`
-						);
-					return param_value;
-				})
-			)
-			.filter(Boolean)
-			.join('/')
-	);
+	return base + resolve_route(id, params);
 }

packages/kit/src/runtime/app/paths.js

@@ -1,5 +1,5 @@
 import * as devalue from 'devalue';
-import { json } from '../../../exports/index.js';
+import { error, json } from '../../../exports/index.js';
 import { normalize_error } from '../../../utils/error.js';
 import { is_form_content_type, negotiate } from '../../../utils/http.js';
 import { HttpError, Redirect, ActionFailure } from '../../control.js';

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

@@ -214,3 +214,49 @@ function escape(str) {
 			.replace(/[.*+?^${}()|\\]/g, '\\$&')
 	);
 }
+
+const basic_param_pattern = /\[(\[)?(\.\.\.)?(\w+?)(?:=(\w+))?\]\]?/g;
+
+/**
+ * Populate a route ID with params to resolve a pathname.
+ * @example
+ * ```js
+ * resolveRoute(
+ *   `/blog/[slug]/[...somethingElse]`,
+ *   {
+ *     slug: 'hello-world',
+ *     somethingElse: 'something/else'
+ *   }
+ * ); // `/blog/hello-world/something/else`
+ * ```
+ * @param {string} id
+ * @param {Record<string, string | undefined>} params
+ * @returns {string}
+ */
+export function resolve_route(id, params) {
+	const segments = get_route_segments(id);
+	return (
+		'/' +
+		segments
+			.map((segment) =>
+				segment.replace(basic_param_pattern, (_, optional, rest, name) => {
+					const param_value = params[name];
+
+					// This is nested so TS correctly narrows the type
+					if (!param_value) {
+						if (optional) return '';
+						if (rest && param_value !== undefined) return '';
+						throw new Error(`Missing parameter '${name}' in route ${id}`);
+					}
+
+					if (param_value.startsWith('/') || param_value.endsWith('/'))
+						throw new Error(
+							`Parameter '${name}' in route ${id} cannot start or end with a slash -- this would cause an invalid route like foo//bar`
+						);
+					return param_value;
+				})
+			)
+			.filter(Boolean)
+			.join('/')
+	);
+}