validation

Author: Rich-Harris

packages/svelte/src/compiler/phases/2-analyze/validation.js

@@ -865,6 +865,12 @@ function validate_call_expression(node, scope, path) {
 			error(node, 'invalid-rune-args-length', rune, [1]);
 		}
 	}
+
+	if (rune === '$state.snapshot') {
+		if (node.arguments.length !== 1) {
+			error(node, 'invalid-rune-args-length', rune, [1]);
+		}
+	}
 }
 
 /**

packages/svelte/src/compiler/phases/3-transform/client/visitors/javascript-runes.js

@@ -389,11 +389,10 @@ export const javascript_visitors_runes = {
 		}
 
 		if (rune === '$state.snapshot') {
-			const arg =
-				node.arguments.length > 0
-					? /** @type {import('estree').Expression} */ (context.visit(node.arguments[0]))
-					: b.id('undefined');
-			return b.call('$.snapshot', arg);
+			return b.call(
+				'$.snapshot',
+				/** @type {import('estree').Expression} */ (context.visit(node.arguments[0]))
+			);
 		}
 
 		if (rune === '$effect.root') {

packages/svelte/src/compiler/phases/3-transform/server/transform-server.js

@@ -794,11 +794,7 @@ const javascript_visitors_runes = {
 		}
 
 		if (rune === '$state.snapshot') {
-			const arg =
-				node.arguments.length > 0
-					? /** @type {import('estree').Expression} */ (context.visit(node.arguments[0]))
-					: b.id('undefined');
-			return context.visit(arg);
+			return /** @type {import('estree').Expression} */ (context.visit(node.arguments[0]));
 		}
 
 		if (rune === '$inspect' || rune === '$inspect().with') {

packages/svelte/tests/compiler-errors/samples/runes-wrong-state-snapshot-args/_config.js

@@ -0,0 +1,8 @@
+import { test } from '../../test';
+
+export default test({
+	error: {
+		code: 'invalid-rune-args-length',
+		message: '$state.snapshot can only be called with 1 argument'
+	}
+});

packages/svelte/tests/compiler-errors/samples/runes-wrong-state-snapshot-args/main.svelte

@@ -0,0 +1,3 @@
+<script>
+	const foo = $state.snapshot();
+</script>

sites/svelte-5-preview/src/routes/docs/content/01-api/02-runes.md

@@ -40,7 +40,7 @@ class Todo {
 
 > In this example, the compiler transforms `done` and `text` into `get`/`set` methods on the class prototype referencing private fields
 
-Objects and arrays [are made deeply reactive](/#H4sIAAAAAAAAE42QwWrDMBBEf2URhUhUNEl7c21DviPOwZY3jVpZEtIqUBz9e-UUt9BTj7M784bdmZ21wciq48xsPyGr2MF7Jhl9-kXEKxrCoqNLQS2TOqqgPbWd7cgggU3TgCFCAw-RekJ-3Et4lvByEq-drbe_dlsPichZcFYZrT6amQto2pXw5FO88FUYtG90gUfYi3zvWrYL75vxL57zfA07_zfr23k1vjtt-aZ0bQTcbrDL5ZifZcAxKeS8lzDc8X0xDhJ2ItdbX1jlOZMb9VnjyCoKCfMpfwG975NFVwEAAA==) by wrapping with with [`Proxies`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy):
+Objects and arrays [are made deeply reactive](/#H4sIAAAAAAAAE42QwWrDMBBEf2URhUhUNEl7c21DviPOwZY3jVpZEtIqUBz9e-UUt9BTj7M784bdmZ21wciq48xsPyGr2MF7Jhl9-kXEKxrCoqNLQS2TOqqgPbWd7cgggU3TgCFCAw-RekJ-3Et4lvByEq-drbe_dlsPichZcFYZrT6amQto2pXw5FO88FUYtG90gUfYi3zvWrYL75vxL57zfA07_zfr23k1vjtt-aZ0bQTcbrDL5ZifZcAxKeS8lzDc8X0xDhJ2ItdbX1jlOZMb9VnjyCoKCfMpfwG975NFVwEAAA==) by wrapping them with [`Proxies`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy):
 
 ```svelte
 <script>