eslint-plugin-vue

Official ESLint plugin for Vue.js

❗ Attention - this is documentation for version 5.x ❗

This branch contains eslint-plugin-vue@next which is a pre-released 5.0, but it's not the default version that you get with npm install eslint-plugin-vue. In order to install this you need to specify either "eslint-plugin-vue": "next" in package.json or do npm install eslint-plugin-vue@next.

Please try it and report any issues that you might have encountered.

If you want to check previous releases go here.

🎨 Playground on the Web

You can try this plugin on the Web.

• https://mysticatea.github.io/vue-eslint-demo/

❕ Requirements

• ESLint ^5.0.0.
• Node.js >=6.5.0

💿 Installation

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

🚀 Usage

Create .eslintrc.* file to configure rules. See also: http://eslint.org/docs/user-guide/configuring.

Example .eslintrc.js:

module.exports = {
  extends: [
    // add more generic rulesets here, such as:
    // 'eslint:recommended',
    'plugin:vue/essential'
  ],
  rules: {
    // override/add rules settings here, such as:
    // 'vue/no-unused-vars': 'error'
  }
}

Single File Components

ESLint only targets .js files by default. You must include the .vue extension using the --ext option or a glob pattern.

Examples:

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

Attention

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

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

If you however want to take advantage of our rules in any of your custom objects that are Vue components, you might need to use special comment // @vue/component that marks 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)
})

eslint-disable functionality in <template>

You can use <!-- eslint-disable -->-like HTML comments in <template> of .vue files. 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, please disable vue/comment-directive rule.

⚙️ Configs

This plugin provides four predefined configs:

• plugin:vue/base - Settings and rules to enable correct ESLint parsing
• plugin:vue/essential - Above, 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

💡 Rules

Rules are grouped by priority to help you understand their purpose. The --fix option on the command line automatically fixes problems reported by rules which have a wrench 🔧 below.

Base Rules (Enabling Correct ESLint Parsing)

Enforce all the rules in this category, as well as all higher priority rules, with:

{
  "extends": "plugin:vue/base"
}

	Rule ID	Description
	vue/comment-directive	support comment-directives in <template>
	vue/jsx-uses-vars	prevent variables used in JSX to be marked as unused

Priority A: Essential (Error Prevention)

Enforce all the rules in this category, as well as all higher priority rules, with:

{
  "extends": "plugin:vue/essential"
}

	Rule ID	Description
	vue/no-async-in-computed-properties	disallow asynchronous actions in computed properties
	vue/no-dupe-keys	disallow duplication of field names
	vue/no-duplicate-attributes	disallow duplication of attributes
	vue/no-parsing-error	disallow parsing errors in <template>
	vue/no-reserved-keys	disallow overwriting reserved keys
🔧	vue/no-shared-component-data	enforce component's data property to be a function
	vue/no-side-effects-in-computed-properties	disallow side effects in computed properties
	vue/no-template-key	disallow key attribute on <template>
	vue/no-textarea-mustache	disallow mustaches in <textarea>
	vue/no-unused-components	disallow registering components that are not used inside templates
	vue/no-unused-vars	disallow unused variable definitions of v-for directives or scope attributes
	vue/no-use-v-if-with-v-for	disallow use v-if on the same element as v-for
	vue/require-component-is	require v-bind:is of <component> elements
🔧	vue/require-prop-type-constructor	require prop type to be a constructor
	vue/require-render-return	enforce render function to always return value
	vue/require-v-for-key	require v-bind:key with v-for directives
	vue/require-valid-default-prop	enforce props default values to be valid
	vue/return-in-computed-property	enforce that a return statement is present in computed property
	vue/use-v-on-exact	enforce usage of exact modifier on v-on
	vue/valid-template-root	enforce valid template root
	vue/valid-v-bind	enforce valid v-bind directives
	vue/valid-v-cloak	enforce valid v-cloak directives
	vue/valid-v-else-if	enforce valid v-else-if directives
	vue/valid-v-else	enforce valid v-else directives
	vue/valid-v-for	enforce valid v-for directives
	vue/valid-v-html	enforce valid v-html directives
	vue/valid-v-if	enforce valid v-if directives
	vue/valid-v-model	enforce valid v-model directives
	vue/valid-v-on	enforce valid v-on directives
	vue/valid-v-once	enforce valid v-once directives
	vue/valid-v-pre	enforce valid v-pre directives
	vue/valid-v-show	enforce valid v-show directives
	vue/valid-v-text	enforce valid v-text directives

Priority B: Strongly Recommended (Improving Readability)

Enforce all the rules in this category, as well as all higher priority rules, with:

{
  "extends": "plugin:vue/strongly-recommended"
}

	Rule ID	Description
🔧	vue/attribute-hyphenation	enforce attribute naming style on custom components in template
🔧	vue/component-name-in-template-casing	enforce specific casing for the component naming style in template
🔧	vue/html-closing-bracket-newline	require or disallow a line break before tag's closing brackets
🔧	vue/html-closing-bracket-spacing	require or disallow a space before tag's closing brackets
🔧	vue/html-end-tags	enforce end tag style
🔧	vue/html-indent	enforce consistent indentation in <template>
🔧	vue/html-self-closing	enforce self-closing style
🔧	vue/max-attributes-per-line	enforce the maximum number of attributes per line
🔧	vue/multiline-html-element-content-newline	require a line break before and after the contents of a multiline element
🔧	vue/mustache-interpolation-spacing	enforce unified spacing in mustache interpolations
🔧	vue/name-property-casing	enforce specific casing for the name property in Vue components
🔧	vue/no-multi-spaces	disallow multiple spaces
🔧	vue/no-spaces-around-equal-signs-in-attribute	disallow spaces around equal signs in attribute
	vue/no-template-shadow	disallow variable declarations from shadowing variables declared in the outer scope
🔧	vue/prop-name-casing	enforce specific casing for the Prop name in Vue components
	vue/require-default-prop	require default value for props
	vue/require-prop-types	require type definitions in props
🔧	vue/singleline-html-element-content-newline	require a line break before and after the contents of a singleline element
🔧	vue/v-bind-style	enforce v-bind directive style
🔧	vue/v-on-style	enforce v-on directive style

Priority C: Recommended (Minimizing Arbitrary Choices and Cognitive Overhead)

Enforce all the rules in this category, as well as all higher priority rules, with:

{
  "extends": "plugin:vue/recommended"
}

	Rule ID	Description
🔧	vue/attributes-order	enforce order of attributes
🔧	vue/html-quotes	enforce quotes style of HTML attributes
	vue/no-v-html	disallow use of v-html to prevent XSS attack
🔧	vue/order-in-components	enforce order of properties in components
	vue/this-in-template	enforce usage of this in template

Uncategorized

	Rule ID	Description
🔧	vue/script-indent	enforce consistent indentation in <script>

Deprecated

• ⚠️ We're going to remove deprecated rules in the next major release. Please migrate to successor/new rules.
• 😇 We don't fix bugs which are in deprecated rules since we don't have enough resources.

Rule ID	Replaced by
vue/no-confusing-v-for-v-if	vue/no-use-v-if-with-v-for

👫 FAQ

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

The most rules of eslint-plugin-vue require vue-eslint-parser to check <template> ASTs.

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

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

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

- "parser": "babel-eslint",
  "parserOptions": {
+     "parser": "babel-eslint",
      "ecmaVersion": 2017,
      "sourceType": "module"
  }

The vue-eslint-parser uses the parser which is set by parserOptions.parser to parse scripts.

Why doesn't it work on .vue file?

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"
  ]

2. Make sure your tool is set to lint .vue files.

• CLI targets only .js files by default. You have to specify additional extensions by --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.
• VSCode targets only JavaScript or HTML files by default. You have to add "vue" to the "eslint.validate" array in vscode settings. e.g. "eslint.validate": [ "javascript", "javascriptreact", "vue" ]
• If you use Vetur plugin in VSCode - set "vetur.validation.template": false to avoid default Vetur template validation. Check out vetur documentation for more info.
• For Atom editor, you need to go into Settings -> Packages -> linter-eslint, under the option “List of scopes to run eslint on”, add text.html.vue.
• For Sublime Text, you need to open command-pallete via cmd+shift+p (cmd => ctrl for windows) and type "Preferences: SublimeLinter Settings", paste to the config on the right side:

{
  "linters": {
    "eslint": {
      "selector": "source.js, text.html.vue"
    }
  }
}

⚓ Semantic Versioning Policy

This plugin follows semantic versioning and ESLint's Semantic Versioning Policy.

📰 Changelog

We're using GitHub Releases.

🍻 Contribution guide

In order to add a new rule, you should:

• Create issue on GH with description of proposed rule
• Generate a new rule using the official yeoman generator
• Run npm start
• Write test scenarios & implement logic
• Describe the rule in the generated docs file
• Make sure all tests are passing
• Run npm run lint and fix any errors
• Run npm run update in order to update readme and recommended configuration
• Create PR and link created issue in description

We're more than happy to see potential contributions, so don't hesitate. If you have any suggestions, ideas or problems feel free to add new issue, but first please make sure your question does not repeat previous ones.

Working with rules

Before you start writing new rule, please read the official ESLint guide.

Next in order to get an idea how does the AST of the code that you want to check looks like, you can use one of the following applications:

• astexplorer.net - best tool to inspect ASTs, but it doesn't support Vue templates yet
• ast.js.org - not fully featured, but supports Vue templates syntax

Since single file components in Vue are not plain JavaScript, we can't use the default parser, and we had to introduce additional one: vue-eslint-parser, that generates enhanced AST with nodes that represent specific parts of the template syntax, as well as what's inside the <script> tag.

To know more about certain nodes in produced ASTs, go here:

• ESTree docs
• vue-eslint-parser AST docs

The vue-eslint-parser provides few useful parser services, to help traverse the produced AST and access tokens of the template:

• context.parserServices.defineTemplateBodyVisitor(visitor, scriptVisitor)
• context.parserServices.getTemplateBodyTokenStore()

Check out an example rule to get a better understanding of how these work.

Please be aware that regarding what kind of code examples you'll write in tests, you'll have to accordingly setup the parser in RuleTester (you can do it on per test case basis though). See an example here

If you'll stuck, remember there are plenty of rules you can learn from already, and if you can't find the right solution - don't hesitate to reach out in issues. We're happy to help!

🔒 License

See the LICENSE file for license rights and limitations (MIT).