fix: handle patterns in destructured literals

.changeset/lucky-knives-crash.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: handle destructured primitive literals

packages/playground/compile.js

@@ -0,0 +1,6 @@
+import { readFileSync } from 'fs';
+import { compile } from '../svelte/src/compiler/index.js';
+
+const code = readFileSync('src/App.svelte', 'utf8');
+
+console.log(compile(code));

packages/svelte/src/compiler/compile/Component.js

@@ -1339,37 +1339,34 @@ export default class Component {
 		for (let i = 0; i < body.length; i += 1) {
 			const node = body[i];
 			if (node.type === 'VariableDeclaration') {
-				const all_hoistable = node.declarations.every(
-					/** @param {any} d */ (d) => {
-						if (!d.init) return false;
-						if (d.init.type !== 'Literal') return false;
-						// everything except const values can be changed by e.g. svelte devtools
-						// which means we can't hoist it
-						if (node.kind !== 'const' && this.compile_options.dev) return false;
-						const { name } = /** @type {import('estree').Identifier} */ (d.id);
+				const all_hoistable = node.declarations.every((d) => {
+					if (!d.init) return false;
+					if (d.init.type !== 'Literal') return false;
+					// everything except const values can be changed by e.g. svelte devtools
+					// which means we can't hoist it
+					if (node.kind !== 'const' && this.compile_options.dev) return false;
+					for (const name of extract_names(d.id)) {
 						const v = this.var_lookup.get(name);
 						if (v.reassigned) return false;
 						if (v.export_name) return false;
-						if (this.var_lookup.get(name).reassigned) return false;
+
 						if (
 							this.vars.find(
 								/** @param {any} variable */ (variable) => variable.name === name && variable.module
 							)
 						) {
 							return false;
 						}
-						return true;
 					}
-				);
+					return true;
+				});
 				if (all_hoistable) {
-					node.declarations.forEach(
-						/** @param {any} d */ (d) => {
-							const variable = this.var_lookup.get(
-								/** @type {import('estree').Identifier} */ (d.id).name
-							);
+					node.declarations.forEach((d) => {
+						for (const name of extract_names(d.id)) {
+							const variable = this.var_lookup.get(name);
 							variable.hoistable = true;
 						}
-					);
+					});
 					hoistable_nodes.add(node);
 					body.splice(i--, 1);
 					this.fully_hoisted.push(node);

packages/svelte/test/js/samples/hoisted-const/expected.js

@@ -15,7 +15,7 @@ function create_fragment(ctx) {
 	return {
 		c() {
 			b = element("b");
-			b.textContent = `${get_answer()}`;
+			b.textContent = `${get_answer()} ${length}`;
 		},
 		m(target, anchor) {
 			insert(target, b, anchor);
@@ -32,6 +32,7 @@ function create_fragment(ctx) {
 }
 
 const ANSWER = 42;
+const { length } = 'abc';
 
 function get_answer() {
 	return ANSWER;

packages/svelte/test/js/samples/hoisted-const/input.svelte

@@ -1,6 +1,7 @@
 <script>
 	const ANSWER = 42;
+	const { length } = 'abc';
 	function get_answer() { return ANSWER; }
 </script>
 
-<b>{get_answer()}</b>
+<b>{get_answer()} {length}</b>

packages/svelte/vitest.config.js

@@ -22,6 +22,7 @@ export default defineConfig({
 	test: {
 		dir: 'test',
 		reporters: ['dot'],
+		include: ['**/*.test.js'],
 		exclude: [...configDefaults.exclude, '**/samples/**'],
 		globalSetup: './test/vitest-global-setup.js'
 	}