# Migration Guide

# From `eslint-plugin-svelte3`

You can not use both eslint-plugin-svelte3 and eslint-plugin-svelte at same time. So before start to use this plugin, you need to remove eslint-plugin-svelte3’s stuff from both package.json and .eslintrc.*.

Note: If you want to know difference between eslint-plugin-svelte and eslint-plugin-svelte3, Please read the reason for deprecating eslint-plugin-svelte3 in eslint-plugin-svelte3 README.

Note: If you’re using TypeScript, maybe you get Parsing error: "parserOptions.project" has been set for @typescript-eslint/parser. error at some configuration files.
In this case, please refer this GitHub comment to solve it.

# From `eslint-plugin-svelte` v1 To v2

eslint-plugin-svelte v1 was an alias for eslint-plugin-svelte3, but eslint-plugin-svelte v2 is now an independent eslint-plugin.

If you want the previous behavior, replace it with eslint-plugin-svelte3.

# From `@ota-meshi/eslint-plugin-svelte`

@ota-meshi/eslint-plugin-svelte has been renamed to eslint-plugin-svelte.
Therefore, you need to replace the package name, and the presets, rules, and settings specified in the configuration.

package.json
Replace the package name.

-  "@ota-meshi/eslint-plugin-svelte": "^0.X.X"
+  "eslint-plugin-svelte": "^X.X.X"

.eslintrc.*
Replace @ota-meshi/svelte with svelte as a string.
Examples:

Presets

  "extends": [
-    "plugin:@ota-meshi/svelte/recommended"
+    "plugin:svelte/recommended"
  ],

Rules

  "rules": {
-    "@ota-meshi/svelte/no-dupe-else-if-blocks": "error",
+    "svelte/no-dupe-else-if-blocks": "error",
-    "@ota-meshi/svelte/button-has-type": "error",
+    "svelte/button-has-type": "error",
  },

settings

  "settings": {
-    "@ota-meshi/svelte": { ... }
+    "svelte": { ... }
  },

# From `eslint-plugin-svelte` v2 To v3

This section explains the necessary changes when upgrading from eslint-plugin-svelte v2 to v3.
v3 includes support for ESLint Flat Config only, changes to the recommended rule set, and other breaking changes.

# Breaking Changes

# 1. Minimum Node.js Version Requirement

v3 requires one of the following Node.js versions:

^18.20.4
^20.18.0
>=22.10.0

# 2. ESLint Flat Config Only

.eslintrc.js and .eslintrc.json are no longer supported.
You must use Flat Config (eslint.config.js).
See README for more details.

# 3. ESLint Version Requirement

v3 requires ESLint 8.57.1 or later (including v9.x).

# 4. Changes to Recommended Rule Set

The following rules are now included in recommended:
- svelte/infinite-reactive-loop
- svelte/no-dom-manipulating
- svelte/no-dupe-on-directives
- svelte/no-reactive-reassign
- svelte/require-event-dispatcher-types
- Many others (See Changelog for more details)
svelte/valid-compile has been removed from recommended.

# 5. Deprecated Rules

svelte/no-dynamic-slot-name is deprecated.
svelte/no-goto-without-base is deprecated and replaced with svelte/no-navigation-without-base.

# New Features & Improvements

# 1. Support for Svelte 5

Rules such as no-not-function-handler and valid-prop-names-in-kit-pages now support Svelte 5.

# 2. New Rules

consistent-selector-style: Enforce consistent selector styles.
no-useless-children-snippet: Prevent unnecessary {@children} usage.
prefer-const: Prefer const over let.
no-navigation-without-base: Ensure proper usage of goto().

# Migration Steps

# 1. Upgrade Package

npm install eslint-plugin-svelte@3

# 2. Check Node.js Version

node -v

Ensure it is v18.20.4 or later.

# 3. Check ESLint Version

npx eslint -v

Ensure it is 8.57.1 or later (or 9.x).

# 4. Use Flat Config (`eslint.config.js`)

Remove .eslintrc.js and migrate to eslint.config.js.

# 5. Apply the Updated Recommended Rules

If using recommended, check the impact of newly added rules.

# 6. Replace Deprecated Rules

Replace no-goto-without-base with no-navigation-without-base.