user-guide.md

User Guide

Installation

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

Note

Requirements:

• ESLint v8.57.1, v9.0.0, and above
• Node.js v18.20.4, v20.18.0, v22.10.0, and above

Usage

Use the eslint.config.js file to configure rules. For more details, see the ESLint documentation.

Configuration

JavaScript project

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

/** @type {import('eslint').Linter.Config[]} */
export default [
  js.configs.recommended,
  ...svelte.configs.recommended,
  {
    languageOptions: {
      globals: {
        ...globals.browser,
        ...globals.node // Add this if you are using SvelteKit in non-SPA mode
      }
    }
  },
  {
    files: ['**/*.svelte', '**/*.svelte.js'],
    languageOptions: {
      parserOptions: {
        // We recommend importing and specifying svelte.config.js.
        // By doing so, some rules in eslint-plugin-svelte will automatically read the configuration and adjust their behavior accordingly.
        // While certain Svelte settings may be statically loaded from svelte.config.js even if you don’t specify it,
        // explicitly specifying it ensures better compatibility and functionality.
        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 js from '@eslint/js';
import svelte from 'eslint-plugin-svelte';
import globals from 'globals';
import ts from 'typescript-eslint';
import svelteConfig from './svelte.config.js';

export default ts.config(
  js.configs.recommended,
  ...ts.configs.recommended,
  ...svelte.configs.recommended,
  {
    languageOptions: {
      globals: {
        ...globals.browser,
        ...globals.node
      }
    }
  },
  {
    files: ['**/*.svelte', '**/*.svelte.ts', '**/*.svelte.js'],
    // See more details at: https://typescript-eslint.io/packages/parser/
    languageOptions: {
      parserOptions: {
        projectService: true,
        extraFileExtensions: ['.svelte'], // Add support for additional file extensions, such as .svelte
        parser: ts.parser,
        // Specify a parser for each language, if needed:
        // parser: {
        //   ts: ts.parser,
        //   js: espree,    // Use espree for .js files (add: import espree from 'espree')
        //   typescript: ts.parser
        // },

        // We recommend importing and specifying svelte.config.js.
        // By doing so, some rules in eslint-plugin-svelte will automatically read the configuration and adjust their behavior accordingly.
        // While certain Svelte settings may be statically loaded from svelte.config.js even if you don’t specify it,
        // explicitly specifying it ensures better compatibility and functionality.
        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:

• eslintPluginSvelte.configs.base ... Enables correct Svelte parsing.
• eslintPluginSvelte.configs.recommended ... Includes base configuration, plus rules to prevent errors or unintended behavior.
• eslintPluginSvelte.configs.prettier ... Disables rules that may conflict with Prettier. You still need to configure Prettier to work with Svelte manually, for example, by using prettier-plugin-svelte.
• eslintPluginSvelte.configs.all ... Includes all available rules. Note: This configuration is not recommended for production use, as it changes with every minor and major version of eslint-plugin-svelte. 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 [
  // ...
  {
    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:

{
  "eslint.validate": ["javascript", "javascriptreact", "svelte"]
}

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.