# User Guide

# 💿 Installation

Via vue-cli (Recommended):

vue add @vue/cli-plugin-eslint

Via npm (opens new window):

npm install --save-dev eslint eslint-plugin-vue

Via yarn (opens new window):

yarn add -D eslint eslint-plugin-vue

Requirements

  • ESLint v6.2.0 and above
  • Node.js v8.10.0 and above

We have started supporting ESLint v8.0.0 beta, but note that beta support will be dropped once the stable version is released.

# 📖 Usage

# Configuration

Use .eslintrc.* file to configure rules. See also: https://eslint.org/docs/user-guide/configuring (opens new window).

Example .eslintrc.js:

module.exports = {
  extends: [
    // add more generic rulesets here, such as:
    // 'eslint:recommended',
    'plugin:vue/vue3-recommended',
    // 'plugin:vue/recommended' // Use this if you are using Vue.js 2.x.
  ],
  rules: {
    // override/add rules settings here, such as:
    // 'vue/no-unused-vars': 'error'
  }
}

See the rule list to get the extends & rules that this plugin provides.

# Bundle Configurations

This plugin provides some predefined configs. You can use the following configs by adding them to extends.

  • "plugin:vue/base" ... Settings and rules to enable correct ESLint parsing.
  • Configurations for using Vue.js 3.x.
    • "plugin:vue/vue3-essential" ... base, plus rules to prevent errors or unintended behavior.
    • "plugin:vue/vue3-strongly-recommended" ... Above, plus rules to considerably improve code readability and/or dev experience.
    • "plugin:vue/vue3-recommended" ... Above, plus rules to enforce subjective community defaults to ensure consistency.
  • Configurations for using Vue.js 2.x.
    • "plugin:vue/essential" ... base, plus rules to prevent errors or unintended behavior.
    • "plugin:vue/strongly-recommended" ... Above, plus rules to considerably improve code readability and/or dev experience.
    • "plugin:vue/recommended" ... Above, plus rules to enforce subjective community defaults to ensure consistency

Reporting rules

By default all rules from base and essential categories report ESLint errors. Other rules - because they're not covering potential bugs in the application - report warnings. What does it mean? By default - nothing, but if you want - you can set up a threshold and break the build after a certain amount of warnings, instead of any. More information here (opens new window).

Status of Vue.js 3.x supports

This plugin supports the basic syntax of Vue.js 3.2, <script setup>, and CSS variable injection, but the ref sugar, an experimental feature of Vue.js 3.2, is not yet supported.
If you have issues with these, please also refer to the FAQ. If you can't find a solution, search for the issue and if the issue doesn't exist, open a new issue.

# Running ESLint from the command line

If you want to run eslint from the command line, make sure you include the .vue extension using the --ext option (opens new window) or a glob pattern, because ESLint targets only .js files by default.

Examples:

eslint --ext .js,.vue src
eslint "src/**/*.{js,vue}"

TIP

If you installed @vue/cli-plugin-eslint (opens new window), you should have the lint script added to your package.json. That means you can just run yarn lint or npm run lint.

# How to use a custom parser?

If you want to use custom parsers such as @babel/eslint-parser (opens new window) or @typescript-eslint/parser (opens new window), you have to use the parserOptions.parser option instead of the parser option. Because this plugin requires vue-eslint-parser (opens new window) to parse .vue files, this plugin doesn't work if you overwrite the parser option.

- "parser": "@typescript-eslint/parser",
+ "parser": "vue-eslint-parser",
  "parserOptions": {
+     "parser": "@typescript-eslint/parser",
      "sourceType": "module"
  }

The parserOptions.parser option can also specify an object to specify multiple parsers. See vue-eslint-parser README (opens new window) for more details.

# How does ESLint detect components?

All component-related rules are applied to code that passes any of the following checks:

  • Vue.component() expression
  • Vue.extend() expression
  • Vue.mixin() expression
  • app.component() expression
  • app.mixin() expression
  • createApp() expression
  • defineComponent() expression
  • export default {} in .vue or .jsx file

However, if you want to take advantage of the rules in any of your custom objects that are Vue components, you might need to use the special comment // @vue/component that marks an object in the next line as a Vue component in any file, e.g.:

// @vue/component
const CustomComponent = {
  name: 'custom-component',
  template: '<div></div>'
}
Vue.component('AsyncComponent', (resolve, reject) => {
  setTimeout(() => {
    // @vue/component
    resolve({
      name: 'async-component',
      template: '<div></div>'
    })
  }, 500)
})

# Disabling rules via <!-- eslint-disable -->

You can use <!-- eslint-disable -->-like HTML comments in the <template> and in the block level of .vue files to disable a certain rule temporarily.

For example:

<template>
  <!-- eslint-disable-next-line vue/max-attributes-per-line -->
  <div a="1" b="2" c="3" d="4">
  </div>
</template>

If you want to disallow eslint-disable functionality in <template>, disable the vue/comment-directive rule.

# Parser Options

This plugin uses vue-eslint-parser (opens new window). For parserOptions, you can use the vueFeatures options of vue-eslint-parser.

{
  "parser": "vue-eslint-parser",
  "parserOptions": {
    "vueFeatures": {
      "filter": true,
      "interpolationAsNonHTML": false,
    }
  }
}

See the parserOptions.vueFeatures documentation for vue-eslint-parser (opens new window) for more details.

# 💻 Editor integrations

# Visual Studio Code

Use the dbaeumer.vscode-eslint (opens new window) extension that Microsoft provides officially.

You have to configure the eslint.validate option of the extension to check .vue files, because the extension targets only *.js or *.jsx files by default.

Example .vscode/settings.json:

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

If you use the Vetur plugin, set "vetur.validation.template": false to avoid default Vetur template validation. Check out vetur documentation (opens new window) for more info.

# Sublime Text

Use Package Control to install SublimeLinter and its ESLint extension SublimeLinter-eslint (opens new window).

In the menu go to Preferences > Package Settings > SublimeLinter > Settings and paste in this:

{
  "linters": {
    "eslint": {
      "selector": "text.html.vue, source.js - meta.attribute-with-value"
    }
  }
}

# Atom editor

Go into Settings -> Packages -> linter-eslint, under the option "List of scopes to run eslint on", add text.html.vue. You may need to restart Atom.

# IntelliJ IDEA / JetBrains WebStorm

In the Settings/Preferences dialog (Cmd+,/Ctrl+Alt+S), choose JavaScript under Languages and Frameworks and then choose ESLint under Code Quality Tools. On the ESLint page that opens, select the Enable checkbox.

If your ESLint configuration is updated (manually or from your version control), open it in the editor and choose Apply ESLint Code Style Rules in the context menu.

read more: JetBrains - ESLint (opens new window)

# ❓ FAQ

# What is the "Use the latest vue-eslint-parser" error?

Most eslint-plugin-vue rules require vue-eslint-parser to check <template> ASTs.

Make sure you have one of the following settings in your .eslintrc:

  • "extends": ["plugin:vue/vue3-recommended"]
  • "extends": ["plugin:vue/base"]

If you already use another parser (e.g. "parser": "@typescript-eslint/parser"), please move it into parserOptions, so it doesn't collide with the vue-eslint-parser used by this plugin's configuration:

- "parser": "@typescript-eslint/parser",
+ "parser": "vue-eslint-parser",
  "parserOptions": {
+     "parser": "@typescript-eslint/parser",
      "ecmaVersion": 2020,
      "sourceType": "module"
  }

See also: "How to use a custom parser?" section.

# Why doesn't it work on .vue files?

  1. Make sure you don't have eslint-plugin-html in your config. The eslint-plugin-html extracts the content from <script> tags, but eslint-plugin-vue requires <script> tags and <template> tags in order to distinguish template and script in single file components.
  "plugins": [
    "vue",
-   "html"
  ]
  1. Make sure your tool is set to lint .vue files.

    • CLI targets only .js files by default. You have to specify additional extensions with the --ext option or glob patterns. E.g. eslint "src/**/*.{js,vue}" or eslint src --ext .vue. If you use @vue/cli-plugin-eslint and the vue-cli-service lint command - you don't have to worry about it.
    • If you are having issues with configuring editor, please read editor integrations

# Conflict with Prettier (opens new window)

Use eslint-config-prettier (opens new window) for Prettier (opens new window) not to conflict with the shareable config provided by this plugin.

Example .eslintrc.js:

module.exports = {
  // ...
  extends: [
    // ...
    // 'eslint:recommended',
    // ...
    'plugin:vue/vue3-recommended',
    // ...
    "prettier"
    // Make sure "prettier" is the last element in this list.
  ],
  // ...
}

If Prettier conflicts with a rule you have set, turn off that rule (opens new window). For example, if you have vue/html-indent configured as error in rules, but it conflicts with Prettier, remove that line:

module.exports = {
  // ...
  rules: {
    // ...
-    "vue/html-indent": "error",
    // ...
  },
  // ...
}

# Using JSX

If you are using JSX, you need to enable JSX in your ESLint configuration.

  "parserOptions": {
      "ecmaVersion": 2020,
      "ecmaFeatures": {
+         "jsx": true
      }
  }

See also ESLint - Specifying Parser Options (opens new window).

The same configuration is required when using JSX with TypeScript (TSX) in the .vue file.
See also here (opens new window).
Note that you cannot use angle-bracket type assertion style (var x = <foo>bar;) when using jsx: true.

# Trouble with Visual Studio Code

  • Turning off the rule in the ESLint configuration file does not ignore the warning.
  • Using the <!-- eslint-disable --> comment does not suppress warnings.
  • Duplicate warnings are displayed.
  • Used @babel/eslint-parser, but the template still show vue/no-parsing-error warnings.

You need to turn off Vetur's template validation by adding vetur.validation.template: false to your .vscode/settings.json.

See also: "Visual Studio Code" section and Vetur - Linting (opens new window).

# Does not work well with <script setup>

# The variables used in the <template> are warned by no-unused-vars rule

You must use vue/script-setup-uses-vars rule.
In your configuration, use the rule set provided by eslint-plugin-vue or enable it rule.

Example .eslintrc.js:

module.exports = {
  // Use the rule set.
  extends: ['plugin:vue/base'],
  rules: {
    // Enable vue/script-setup-uses-vars rule
    'vue/script-setup-uses-vars': 'error',
  }
}

# Compiler macros such as defineProps and defineEmits are warned by no-undef rule

You need to define global variables (opens new window) in your ESLint configuration file.
If you don't want to define global variables, use import { defineProps, defineEmits } from 'vue'.

Example .eslintrc.js:

module.exports = {
  globals: {
    defineProps: "readonly",
    defineEmits: "readonly",
    defineExpose: "readonly",
    withDefaults: "readonly"
  }
}

See also ESLint - Specifying Globals > Using configuration files (opens new window).

# Parsing error with Top Level await

# Using ESLint <= v7.x

The parser espree that comes with ESLint v7.x doesn't understand the syntax of ES2022, so it can't parse the Top Level await either.
However, espree >= v8 can understand the syntax of ES2022 and parse the Top Level await.
You install espree >= v8 and specify "espree" and ES2022 in your configuration, the parser will be able to parse it.

module.exports = {
  parser: 'vue-eslint-parser',
  parserOptions: {
    parser: 'espree', // <-
    ecmaVersion: 2022, // <-
    sourceType: 'module'
  },
}

However, note that the AST generated by espree v8+ may not work well with some rules of ESLint v7.x.

# Using ESLint >= v8.x

You need to specify 2022 or "latest" for parserOptions.ecmaVersion.

module.exports = {
  parserOptions: {
    ecmaVersion: 'latest',
    sourceType: 'module'
  },
}

# Other Problems

Try searching for existing issues. If it does not exist, you should open a new issue and share your repository to reproduce the issue.