Diagnostics service

apps/svelte.dev/scripts/create-tutorial-zip/common/svelte.config.js

@@ -5,15 +5,6 @@ const config = {
 		// Don't do this in your own apps unless you know what you're doing!
 		// See https://kit.svelte.dev/docs/configuration#csrf for more info.
 		csrf: false
-	},
-
-	vitePlugin: {
-		// This enables compile-time warnings to be
-		// visible in the learn.svelte.dev editor
-		onwarn: (warning, defaultHandler) => {
-			console.log('svelte:warnings:%s', JSON.stringify(warning));
-			defaultHandler(warning);
-		}
 	}
 };
 

apps/svelte.dev/src/lib/tutorial/adapters/rollup/index.svelte.ts

@@ -3,16 +3,13 @@ import Bundler from '@sveltejs/repl/bundler';
 import * as yootils from 'yootils';
 import type { Adapter } from '$lib/tutorial';
 import type { File, Item } from 'editor';
-import type { CompileError, Warning } from 'svelte/compiler';
 
 /** Rollup bundler singleton */
 let bundler: Bundler;
 
 export const state = new (class RollupState {
 	progress = $state.raw({ value: 0, text: 'initialising' });
 	bundle = $state.raw<any>(null);
-	errors = $state.raw<Record<string, CompileError | null>>();
-	warnings = $state.raw<Record<string, Warning[]>>({});
 })();
 
 /**
@@ -43,7 +40,7 @@ export async function create(): Promise<Adapter> {
 	let current_stubs = stubs_to_map([]);
 
 	async function compile() {
-		const result = await bundler.bundle(
+		state.bundle = await bundler.bundle(
 			[...current_stubs.values()]
 				// TODO we can probably remove all the SvelteKit specific stuff from the tutorial content once this settles down
 				.filter((f): f is File => f.name.startsWith('/src/lib/') && f.type === 'file')
@@ -53,23 +50,6 @@ export async function create(): Promise<Adapter> {
 					type: f.name.split('.').pop() ?? 'svelte'
 				}))
 		);
-
-		state.bundle = result;
-
-		// TODO this approach is insufficient — we need to get diagnostics for
-		// individual files, not just the bundle as a whole
-		state.errors = {};
-		state.warnings = {};
-
-		if (result.error) {
-			const file = '/src/lib/' + result.error.filename;
-			state.errors[file] = result.error;
-		}
-
-		for (const warning of result?.warnings ?? []) {
-			const file = '/src/lib/' + warning.filename;
-			(state.warnings[file] ??= []).push(warning);
-		}
 	}
 
 	const q = yootils.queue(1);

apps/svelte.dev/src/lib/tutorial/adapters/webcontainer/index.svelte.ts

@@ -8,7 +8,6 @@ import { escape_html } from '../../../utils/escape.js';
 import { ready } from '../common/index.js';
 import type { Adapter } from '$lib/tutorial';
 import type { Item, File } from 'editor';
-import type { CompileError, Warning } from 'svelte/compiler';
 
 const converter = new AnsiToHtml({
 	fg: 'var(--sk-text-3)'
@@ -22,8 +21,6 @@ export const state = new (class WCState {
 	base = $state.raw<string | null>(null);
 	error = $state.raw<Error | null>(null);
 	logs = $state.raw<string[]>([]);
-	errors = $state.raw<Record<string, CompileError | null>>({});
-	warnings = $state.raw<Record<string, Warning[]>>({});
 })();
 
 export async function create(): Promise<Adapter> {
@@ -49,40 +46,14 @@ export async function create(): Promise<Adapter> {
 		}
 	});
 
-	let warnings: Record<string, import('svelte/compiler').Warning[]> = {};
-	let timeout: any;
-
-	function schedule_to_update_warning(msec: number) {
-		clearTimeout(timeout);
-		timeout = setTimeout(() => (state.warnings = { ...warnings }), msec);
-	}
-
 	const log_stream = () =>
 		new WritableStream({
 			write(chunk) {
 				if (chunk === '\x1B[1;1H') {
 					// clear screen
 					state.logs = [];
 				} else if (chunk?.startsWith('svelte:warnings:')) {
-					const warn: Warning = JSON.parse(chunk.slice(16));
-					const filename = (warn.filename!.startsWith('/') ? warn.filename : '/' + warn.filename)!;
-					const current = warnings[filename];
-
-					if (!current) {
-						warnings[filename] = [warn];
-						// the exact same warning may be given multiple times in a row
-					} else if (
-						!current.some(
-							(s) =>
-								s.code === warn.code &&
-								s.position![0] === warn.position![0] &&
-								s.position![1] === warn.position![1]
-						)
-					) {
-						current.push(warn);
-					}
-
-					schedule_to_update_warning(100);
+					// TODO when does this happen?
 				} else {
 					const log = converter.toHtml(escape_html(chunk)).replace(/\n/g, '<br>');
 					state.logs = [...state.logs, log];
@@ -181,17 +152,6 @@ export async function create(): Promise<Adapter> {
 					...force_delete
 				];
 
-				// initialize warnings of written files
-				to_write
-					.filter((stub) => stub.type === 'file' && warnings[stub.name])
-					.forEach((stub) => (warnings[stub.name] = []));
-				// remove warnings of deleted files
-				to_delete
-					.filter((stubname) => warnings[stubname])
-					.forEach((stubname) => delete warnings[stubname]);
-
-				state.warnings = { ...warnings };
-
 				current_stubs = stubs_to_map(stubs);
 
 				// For some reason, server-ready is fired again when the vite dev server is restarted.
@@ -258,10 +218,6 @@ export async function create(): Promise<Adapter> {
 
 					tree[basename] = to_file(file);
 
-					// initialize warnings of this file
-					warnings[file.name] = [];
-					schedule_to_update_warning(100);
-
 					await vm.mount(root);
 
 					if (will_restart) await wait_for_restart_vite();

apps/svelte.dev/src/routes/tutorial/[...slug]/+page.svelte

@@ -316,8 +316,6 @@
 							<section slot="b" class="editor-container">
 								<Editor
 									bind:this={editor}
-									errors={adapter.adapter_state.errors}
-									warnings={adapter.adapter_state.warnings}
 									{workspace}
 									onchange={async (file, contents) => {
 										skip_set_files = true;

apps/svelte.dev/src/routes/tutorial/[...slug]/adapter.svelte.ts

@@ -31,10 +31,6 @@ export const adapter_state = new (class {
 			status: 'initialising'
 		}
 	);
-
-	/** Diagnostics */
-	errors = $derived((use_rollup ? rollup_state.errors : wc_state.errors) || {});
-	warnings = $derived((use_rollup ? rollup_state.warnings : wc_state.warnings) || {});
 })();
 
 if (browser) {

packages/editor/src/lib/Editor.svelte

@@ -14,18 +14,15 @@
 	import { autocomplete_for_svelte } from '@sveltejs/site-kit/codemirror';
 	import type { Diagnostic } from '@codemirror/lint';
 	import { Workspace, type Item, type File } from './Workspace.svelte.js';
-	import type { CompileError, Warning } from 'svelte/compiler';
 	import './codemirror.css';
 
 	interface Props {
-		errors: Record<string, CompileError | null>;
-		warnings: Record<string, Warning[]>;
 		workspace: Workspace;
 		onchange: (file: File, contents: string) => void;
 		autocomplete_filter?: (file: File) => boolean;
 	}
 
-	let { errors, warnings, workspace, onchange, autocomplete_filter = () => true }: Props = $props();
+	let { workspace, onchange, autocomplete_filter = () => true }: Props = $props();
 
 	let container: HTMLDivElement;
 
@@ -171,25 +168,25 @@
 
 		const diagnostics: Diagnostic[] = [];
 
-		const error = null; // TODO should be `errors[workspace.selected_name]` but it's currently a Rollup plugin error...
-		const current_warnings = warnings[workspace.selected_name] || [];
+		const error = workspace.diagnostics[workspace.selected_name]?.error;
+		const current_warnings = workspace.diagnostics[workspace.selected_name]?.warnings ?? [];
 
 		if (error) {
-			// diagnostics.push({
-			// 	severity: 'error',
-			// 	from: error.position![0],
-			// 	to: error.position![1],
-			// 	message: error.message,
-			// 	renderMessage: () => {
-			// 		// TODO expose error codes, so we can link to docs in future
-			// 		const span = document.createElement('span');
-			// 		span.innerHTML = `${error.message
-			// 			.replace(/&/g, '&amp;')
-			// 			.replace(/</g, '&lt;')
-			// 			.replace(/`(.+?)`/g, `<code>$1</code>`)}`;
-			// 		return span;
-			// 	}
-			// });
+			diagnostics.push({
+				severity: 'error',
+				from: error.position![0],
+				to: error.position![1],
+				message: error.message,
+				renderMessage: () => {
+					const span = document.createElement('span');
+					span.innerHTML = `${error.message
+						.replace(/&/g, '&amp;')
+						.replace(/</g, '&lt;')
+						.replace(/`(.+?)`/g, `<code>$1</code>`)} <strong>(${error.code})</strong>`;
+
+					return span;
+				}
+			});
 		}
 
 		for (const warning of current_warnings) {

packages/editor/src/lib/Workspace.svelte.ts

@@ -1,3 +1,6 @@
+import type { CompileError, Warning } from 'svelte/compiler';
+import { get_diagnostics } from './diagnostics';
+
 export interface File {
 	type: 'file';
 	name: string;
@@ -14,11 +17,18 @@ export interface Directory {
 
 export type Item = File | Directory;
 
+export interface Diagnostics {
+	error: CompileError | null;
+	warnings: Warning[];
+}
+
 export class Workspace {
 	files = $state.raw<Item[]>([]);
 	creating = $state.raw<{ parent: string; type: 'file' | 'directory' } | null>(null);
 	selected_name = $state<string | null>(null);
 
+	diagnostics = $state<Record<string, Diagnostics>>({});
+
 	#onupdate: (file: File) => void;
 	#onreset: (items: Item[]) => void;
 
@@ -37,6 +47,21 @@ export class Workspace {
 		this.selected_name = selected_name;
 		this.#onupdate = onupdate;
 		this.#onreset = onreset;
+
+		this.#reset_diagnostics();
+	}
+
+	#reset_diagnostics() {
+		this.diagnostics = {};
+
+		for (const file of this.files) {
+			if (file.type !== 'file') continue;
+			if (!/\.svelte(\.|$)/.test(file.name)) continue;
+
+			get_diagnostics(file).then((diagnostics) => {
+				this.diagnostics[file.name] = diagnostics;
+			});
+		}
 	}
 
 	get selected_file() {
@@ -55,6 +80,10 @@ export class Workspace {
 			return old;
 		});
 
+		get_diagnostics(file).then((diagnostics) => {
+			this.diagnostics[file.name] = diagnostics;
+		});
+
 		this.#onupdate(file);
 	}
 
@@ -67,5 +96,6 @@ export class Workspace {
 		this.files = new_files;
 
 		this.#onreset(new_files);
+		this.#reset_diagnostics();
 	}
 }

packages/editor/src/lib/diagnostics/index.ts

@@ -0,0 +1,40 @@
+import { BROWSER } from 'esm-env';
+import DiagnosticsWorker from './worker?worker';
+import type { Diagnostics, File } from '../Workspace.svelte';
+
+const callbacks = new Map<number, (diagnostics: Diagnostics) => void>();
+
+let worker: Worker;
+
+let uid = 1;
+
+if (BROWSER) {
+	worker = new DiagnosticsWorker();
+
+	worker.addEventListener('message', (event) => {
+		const callback = callbacks.get(event.data.id);
+
+		if (callback) {
+			callback(event.data.payload);
+			callbacks.delete(event.data.id);
+		}
+	});
+}
+
+export function get_diagnostics(file: File): Promise<Diagnostics> {
+	if (!BROWSER) {
+		// TODO this is a bit janky
+		return Promise.resolve({
+			error: null,
+			warnings: []
+		});
+	}
+
+	let id = uid++;
+
+	worker.postMessage({ id, file });
+
+	return new Promise((fulfil) => {
+		callbacks.set(id, fulfil);
+	});
+}

packages/editor/src/lib/diagnostics/worker.ts

@@ -0,0 +1,34 @@
+import { compile, compileModule } from 'svelte/compiler';
+import type { File } from '../Workspace.svelte';
+
+// TODO need to handle Svelte 3/4 for playground
+
+addEventListener('message', (event) => {
+	const { id, file } = event.data as { id: number; file: File };
+
+	const fn = file.name.endsWith('.svelte') ? compile : compileModule;
+
+	try {
+		const result = fn(file.contents, {
+			filename: file.name
+		});
+
+		postMessage({
+			id,
+			payload: {
+				error: null,
+				// @ts-expect-error https://github.com/sveltejs/svelte/issues/13628
+				warnings: result.warnings.map((w) => ({ message: w.message, ...w }))
+			}
+		});
+	} catch (e) {
+		postMessage({
+			id,
+			payload: {
+				// @ts-expect-error
+				error: { message: e.message, ...e },
+				warnings: []
+			}
+		});
+	}
+});

packages/editor/tsconfig.json

@@ -9,7 +9,7 @@
 		"skipLibCheck": true,
 		"sourceMap": true,
 		"strict": true,
-		"module": "NodeNext",
+		"module": "preserve",
 		"moduleResolution": "bundler"
 	}
 }