future-proof

Author: dummdidumm

packages/svelte/src/compiler/migrate/index.js

@@ -10,8 +10,10 @@ import { regex_is_valid_identifier } from '../phases/patterns.js';
 
 /**
  * Does a best-effort migration of Svelte code towards using runes, event attributes and render tags.
+ * May throw an error if the code is too complex to migrate automatically.
+ *
  * @param {string} source
- * @returns {string}
+ * @returns {{ code: string; }}
  */
 export function migrate(source) {
 	try {
@@ -145,7 +147,7 @@ export function migrate(source) {
 			}
 		}
 
-		return str.toString();
+		return { code: str.toString() };
 	} catch (e) {
 		// eslint-disable-next-line no-console
 		console.error('Error while migrating Svelte code');

packages/svelte/types/index.d.ts

@@ -1088,8 +1088,12 @@ declare module 'svelte/compiler' {
 	export const VERSION: string;
 	/**
 	 * Does a best-effort migration of Svelte code towards using runes, event attributes and render tags.
+	 * May throw an error if the code is too complex to migrate automatically.
+	 *
 	 * */
-	export function migrate(source: string): string;
+	export function migrate(source: string): {
+		code: string;
+	};
 	class Scope {
 
 		constructor(root: ScopeRoot, parent: Scope | null, porous: boolean);

sites/svelte-5-preview/src/lib/Repl.svelte

@@ -170,7 +170,7 @@
 			if (file.name === $selected?.name) {
 				return {
 					...file,
-					source: result.source
+					source: result.result.code
 				};
 			}
 			return file;

sites/svelte-5-preview/src/lib/workers/compiler/index.js

@@ -136,19 +136,19 @@ function compile({ id, source, options, return_ast }) {
 /** @param {import("../workers").MigrateMessageData} param0 */
 function migrate({ id, source }) {
 	try {
-		source = svelte.migrate(source);
+		const result = svelte.migrate(source);
 
 		return {
 			id,
-			source
+			result
 		};
 	} catch (err) {
 		// @ts-ignore
 		let message = `/*\nError migrating ${err.filename ?? 'component'}:\n${err.message}\n*/`;
 
 		return {
 			id,
-			source,
+			result: { code: source },
 			error: message
 		};
 	}

sites/svelte-5-preview/src/lib/workers/workers.d.ts

@@ -29,6 +29,6 @@ export type BundleMessageData = {
 
 export type MigrateMessageData = {
 	id: number;
-	source: string;
+	result: { code: string };
 	error?: string;
 };