fix: ignore $state in the prefer-const rule

baseballyama · baseballyama · commit 15e00383cef5 · 2025-02-09T21:20:40.000+09:00
diff --git a/.changeset/sixty-cars-fail.md b/.changeset/sixty-cars-fail.md
@@ -0,0 +1,5 @@
+---
+'eslint-plugin-svelte': patch
+---
+
+fix: ignore `$state` in the `prefer-const` rule
diff --git a/docs/rules/prefer-const.md b/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-->
 
diff --git a/packages/eslint-plugin-svelte/src/rules/prefer-const.ts b/packages/eslint-plugin-svelte/src/rules/prefer-const.ts
@@ -31,7 +31,7 @@ function shouldSkipDeclaration(declaration: TSESTree.Expression | null) {
 		return false;
 	}
 
-	if (callee.type === 'Identifier' && ['$props', '$derived'].includes(callee.name)) {
+	if (callee.type === 'Identifier' && ['$props', '$derived', '$state'].includes(callee.name)) {
 		return true;
 	}
 
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-const/invalid/test01-errors.yaml b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-const/invalid/test01-errors.yaml
@@ -2,10 +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
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-const/invalid/test01-output.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-const/invalid/test01-output.svelte
@@ -1,7 +1,7 @@
 <script>
 	let { prop1, prop2 } = $props();
 	const zero = 0;
-	const state = $state(0);
+	let state = $state(0);
 	const raw = $state.raw(0);
 	const doubled = state * 2;
 	let derived = $derived(state * 2);

-Original file line number
+Diff line change
@@ @@ -0,0 +1,5 @@ @@
 +---
 +'eslint-plugin-svelte': patch
 +---
++
 +fix: ignore `$state` in the `prefer-const` rule
Original file line number	Diff line number	Diff line change
`@@ -31,7 +31,7 @@ function shouldSkipDeclaration(declaration: TSESTree.Expression \| null) {`
`31`	`31`	`return false;`
`32`	`32`	`}`
`33`	`33`
`34`		`- if (callee.type === 'Identifier' && ['$props', '$derived'].includes(callee.name)) {`
	`34`	`+ if (callee.type === 'Identifier' && ['$props', '$derived', '$state'].includes(callee.name)) {`
`35`	`35`	`return true;`
`36`	`36`	`}`
`37`	`37`