fix: ignore $state in the prefer-const rule

Author: baseballyama

.changeset/sixty-cars-fail.md

@@ -0,0 +1,5 @@
+---
+'eslint-plugin-svelte': patch
+---
+
+fix: ignore `$state` in the `prefer-const` rule

docs/rules/prefer-const.md

@@ -14,7 +14,7 @@ since: 'v3.0.0-next.6'
 
 ## :book: Rule Details
 
-This rule reports the same as the base ESLint `prefer-const` rule, except that ignores Svelte reactive values such as `$derived` and `$props`. If this rule is active, make sure to disable the base `prefer-const` rule, as it will conflict with this rule.
+This rule reports the same as the base ESLint `prefer-const` rule, except that ignores Svelte reactive values such as `$derived`, `$state`, and `$props`. If this rule is active, make sure to disable the base `prefer-const` rule, as it will conflict with this rule.
 
 <!--eslint-skip-->
 

packages/eslint-plugin-svelte/src/rules/prefer-const.ts

@@ -31,19 +31,15 @@ function shouldSkipDeclaration(declaration: TSESTree.Expression | null) {
 		return false;
 	}
 
-	if (callee.type === 'Identifier' && ['$props', '$derived'].includes(callee.name)) {
+	if (callee.type === 'Identifier' && ['$props', '$state', '$derived'].includes(callee.name)) {
 		return true;
 	}
 
 	if (callee.type !== 'MemberExpression' || callee.object.type !== 'Identifier') {
 		return false;
 	}
 
-	if (
-		callee.object.name === '$derived' &&
-		callee.property.type === 'Identifier' &&
-		callee.property.name === 'by'
-	) {
+	if (callee.object.name === '$state' || callee.object.name === '$derived') {
 		return true;
 	}
 

packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-const/invalid/test01-errors.yaml

@@ -2,14 +2,6 @@
   line: 3
   column: 6
   suggestions: null
-- message: "'state' is never reassigned. Use 'const' instead."
-  line: 4
-  column: 6
-  suggestions: null
-- message: "'raw' is never reassigned. Use 'const' instead."
-  line: 5
-  column: 6
-  suggestions: null
 - message: "'doubled' is never reassigned. Use 'const' instead."
   line: 6
   column: 6

packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-const/invalid/test01-output.svelte

@@ -1,8 +1,8 @@
 <script>
 	let { prop1, prop2 } = $props();
 	const zero = 0;
-	const state = $state(0);
-	const raw = $state.raw(0);
+	let state = $state(0);
+	let raw = $state.raw(0);
 	const doubled = state * 2;
 	let derived = $derived(state * 2);
 	const calculated = calc();