# User Guide

# Installation

# CLI

The recommended way to get started is to use the CLI.

# new project
npx sv create

# existing project
npx sv add eslint

See the CLI docs for more details.

# Manual Setup

npm install --save-dev svelte eslint eslint-plugin-svelte globals

[!NOTE]

Requirements:

• ESLint v8.57.1, v9.0.0, and above
• Node.js v18.18.0, v20.9.0, v21.1.0 and above

# Usage

Use eslint.config.js to configure rules. See ESLint documentation for more details.

# Configuration

# JavaScript project

// eslint.config.js
import svelteConfig from './svelte.config.js';
import { defineConfig } from 'eslint/config';
import globals from 'globals';
import js from '@eslint/js';
import svelte from 'eslint-plugin-svelte';

export default defineConfig([
  // ...
  js.configs.recommended,
  svelte.configs.recommended,
  {
    languageOptions: {
      globals: {
        ...globals.browser,
        // for Sveltekit in non-SPA mode
        ...globals.node
      }
    }
  },
  {
    files: ['**/*.svelte', '**/*.svelte.js'],
    languageOptions: {
      parserOptions: {
        // explicitly importing allows for better compatibilty and functionality with rules and other tooling that depend on the config file.
        //
        // Note: `eslint --cache` will fail with non-serializable properties.
        // In those cases, please remove the non-serializable properties.
        // svelteConfig: {
        //   ...svelteConfig,
        //   kit: {
        //     ...svelteConfig.kit,
        //     typescript: undefined
        //   }
        // }
        svelteConfig
      }
    }
  },
  {
    rules: {
      // Override or add rule settings here, such as:
      // 'svelte/rule-name': 'error'
    }
  }
]);

# TypeScript project

npm install --save-dev typescript-eslint

// eslint.config.js
import svelteConfig from './svelte.config.js';
import { defineConfig } from 'eslint/config';
import globals from 'globals';
import js from '@eslint/js';
import ts from 'typescript-eslint';
import svelte from 'eslint-plugin-svelte';

export default defineConfig(
  js.configs.recommended,
  ts.configs.recommended,
  svelte.configs.recommended,
  {
    languageOptions: {
      globals: {
        ...globals.browser,
        // for Sveltekit in non-SPA mode
        ...globals.node
      }
    }
    // ...
  },
  {
    files: ['**/*.svelte', '**/*.svelte.ts', '**/*.svelte.js'],
    // See more details at: https://typescript-eslint.io/packages/parser/
    languageOptions: {
      parserOptions: {
        projectService: true,
        // Enable typescript parsing for `.svelte` files.
        extraFileExtensions: ['.svelte'],

        // Specify a parser for each language, if needed:
        // parser: {
        //   ts: ts.parser,
        //   typescript: ts.parser
        //   js: espree,            // add `import espree from 'espree'`
        // },
        parser: ts.parser,

        // explicitly importing allows for better compatibilty and functionality with rules and other tooling that depend on the config file.
        //
        // Note: `eslint --cache` will fail with non-serializable properties.
        // In those cases, please remove the non-serializable properties.
        // svelteConfig: {
        //   ...svelteConfig,
        //   kit: {
        //     ...svelteConfig.kit,
        //     typescript: undefined
        //   }
        // }
        svelteConfig
      }
    }
  },
  {
    rules: {
      // Override or add rule settings here, such as:
      // 'svelte/rule-name': 'error'
    }
  }
);

[!WARNING] The TypeScript parser uses a singleton internally, meaning it only respects the options provided during its initial initialization. If you try to change the options for a different file or override them later, the parser will ignore the new options, which may lead to errors. For more context, see typescript-eslint/typescript-eslint#6778.

# Available Configurations

This plugin provides the following configurations:

• svelte.configs.base - Required for Svelte parsing. Does not include any rules. Ideal for building a custom configurations.
• svelte.configs.recommended - Extends base and includes rules for best practices.
• svelte.configs.prettier - Extends base and disables rules that may conflict with Prettier. Prettier still needs to be configured to work with Svelte, for example, by using prettier-plugin-svelte.
• svelte.configs.all - Not Recommended - Extends base and includes all rules. Subject to change with every major and minor release. Use at your own risk.

For more details, see the rule list to explore the rules provided by this plugin.

# settings.svelte

You can customize the behavior of this plugin using specific settings.

// eslint.config.js
export default defineConfig([
  // ...
  {
    settings: {
      svelte: {
        // Specifies an array of rules to ignore reports within the template.
        // For example, use this to disable rules in the template that may produce unavoidable false positives.
        ignoreWarnings: [
          '@typescript-eslint/no-unsafe-assignment',
          '@typescript-eslint/no-unsafe-member-access'
        ],

        // Specifies options for Svelte compilation.
        // This affects rules that rely on Svelte compilation,
        // such as `svelte/valid-compile` and `svelte/no-unused-svelte-ignore`.
        // Note that this setting does not impact ESLint’s custom parser.
        compileOptions: {
          // Specifies options related to PostCSS. You can disable the PostCSS processing by setting it to false.
          postcss: {
            // Specifies the path to the directory that contains the PostCSS configuration.
            configFilePath: './path/to/my/postcss.config.js'
          }
        },

        // Even if settings.svelte.kit is not specified, the rules will attempt to load information from svelte.config.js.
        // However, if the default behavior does not work as expected, you should specify settings.svelte.kit explicitly.
        // If you are using SvelteKit with a non-default configuration, you need to set the following options.
        // The schema is a subset of SvelteKit’s configuration, so refer to the SvelteKit documentation for more details.
        // https://svelte.dev/docs/kit/configuration
        kit: {
          files: {
            routes: 'src/routes'
          }
        }
      }
    }
  }
  // ...
]);

# Editor Integrations

Visual Studio Code
Install dbaeumer.vscode-eslint.
Configure .svelte files in .vscode/settings.json:

# FAQ

# You’re using TypeScript and the imported *.svelte component types cannot be resolved or appear to be

You can try typescript-eslint-parser-for-extra-files. Note however that it is still an experimental package.
If you know of a better solution than that please let us know.