feat: make it possible to await bundling, retrieve ASTs (#1392)

Useful for use cases like v0 which wants to await the bundle then retrieve the resulting ASTs for further analysis

Author: dummdidumm

packages/repl/src/lib/Bundler.svelte.ts

@@ -56,5 +56,22 @@ export default class Bundler {
 		});
 
 		uid += 1;
+
+		return new Promise<void>((resolve) => {
+			const destroy = $effect.root(() => {
+				let first = true;
+				$effect.pre(() => {
+					this.result;
+					if (first) {
+						first = false;
+					} else {
+						destroy();
+						// This isn't necessarily the result of this bundle call, as it could be
+						// superseeded by another call to `bundle` before the result is set.
+						resolve();
+					}
+				});
+			});
+		});
 	}
 }

packages/repl/src/lib/Repl.svelte

@@ -52,15 +52,16 @@
 		text: true
 	};
 
-	const workspace = new Workspace([dummy], {
+	const workspace: Workspace = new Workspace([dummy], {
 		initial: 'App.svelte',
 		svelte_version: svelteVersion,
 		onupdate() {
 			rebundle();
 			onchange?.();
 		},
 		onreset() {
-			rebundle();
+			// Return promise so we can await it in the workspace
+			return rebundle();
 		}
 	});
 
@@ -74,28 +75,39 @@
 		};
 	}
 
-	// TODO get rid
+	// Our own playground / v0 need this
 	export async function set(data: {
 		files: File[];
 		tailwind?: boolean;
 		aliases?: Record<string, string>;
 	}) {
-		workspace.reset(
+		// Await promise so that users (v0 in this case) can know when the bundling is done
+		await workspace.reset(
 			data.files,
 			{ tailwind: data.tailwind ?? false, aliases: data.aliases },
 			'App.svelte'
 		);
 	}
 
+	// v0 needs this
+	export function get_asts() {
+		return Object.fromEntries(
+			Object.entries(workspace.compiled).map(([name, compiled]) => [
+				name,
+				compiled.result?.ast ?? null
+			])
+		);
+	}
+
 	// TODO get rid
 	export function markSaved() {
 		workspace.mark_saved();
 	}
 
 	const toggleable: ReplContext['toggleable'] = writable(false);
 
-	async function rebundle() {
-		bundler!.bundle(workspace.files as File[], {
+	function rebundle() {
+		return bundler!.bundle(workspace.files as File[], {
 			tailwind: workspace.tailwind,
 			fragments: workspace.compiler_options.fragments,
 			aliases: workspace.aliases

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

@@ -126,7 +126,7 @@ export class Workspace {
 	};
 
 	#onupdate: (file: File) => void;
-	#onreset: (items: Item[]) => void;
+	#onreset: (items: Item[]) => void | Promise<void>;
 
 	// CodeMirror stuff
 	states = new Map<string, EditorState>();
@@ -199,7 +199,7 @@ export class Workspace {
 			initial?: string;
 			readonly?: boolean;
 			onupdate?: (file: File) => void;
-			onreset?: (items: Item[]) => void;
+			onreset?: (items: Item[]) => void | Promise<void>;
 		} = {}
 	) {
 		this.#svelte_version = svelte_version;
@@ -414,8 +414,12 @@ export class Workspace {
 		this.#tailwind = options.tailwind;
 		this.#aliases = options.aliases;
 
-		this.#onreset(new_files);
-		this.#reset_diagnostics();
+		const bundle = this.#onreset(new_files);
+		const diagnostics = this.#reset_diagnostics();
+
+		return Promise.all([bundle, diagnostics])
+			.then(() => {})
+			.catch(() => {});
 	}
 
 	select(name: string) {
@@ -663,22 +667,26 @@ export class Workspace {
 			files = [this.current, ...this.#files.slice(0, i), ...this.#files.slice(i + 1)];
 		}
 
-		for (const file of files) {
-			if (file.type !== 'file') continue;
-			if (!is_svelte_file(file)) continue;
+		const done = files.map((file) => {
+			if (file.type !== 'file') return;
+			if (!is_svelte_file(file)) return;
 
 			seen.push(file.name);
 
-			compile_file(file, this.#svelte_version, this.compiler_options).then((compiled) => {
+			return compile_file(file, this.#svelte_version, this.compiler_options).then((compiled) => {
 				this.compiled[file.name] = compiled;
 			});
-		}
+		});
 
 		for (const key of keys) {
 			if (!seen.includes(key)) {
 				delete this.compiled[key];
 			}
 		}
+
+		return Promise.all(done)
+			.then(() => {})
+			.catch(() => {});
 	}
 
 	#select(file: File) {