This ESLint plugin provides linting rules for YAML.

Usage no npm install needed!

<script type="module">
  import eslintPluginYml from '';



eslint-plugin-yml is ESLint plugin provides linting rules for YAML.

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:name_badge: Features

This ESLint plugin provides linting rules for YAML.

  • You can use ESLint to lint YAML.
  • You can find out the problem with your YAML files.
  • You can apply consistent code styles to your YAML files.
  • Supports Vue SFC custom blocks such as <i18n lang="yaml">.
    Requirements vue-eslint-parser v7.3.0 and above.
  • Supports ESLint directives. e.g. # eslint-disable-next-line
  • You can check your code in real-time using the ESLint editor integrations.

You can check on the Online DEMO.

:question: How is it different from other YAML plugins?

Plugins that do not use AST

e.g. eslint-plugin-yaml

These plugins use the processor to parse and return the results independently, without providing the ESLint engine with AST and source code text.

Plugins don't provide AST, so you can't use directive comments (e.g. # eslint-disable).
Plugins don't provide source code text, so you can't use it with plugins and rules that use text (e.g. eslint-plugin-prettier, eol-last).

eslint-plugin-yml works by providing AST and source code text to ESLint.

:book: Documentation

See documents.

:cd: Installation

npm install --save-dev eslint eslint-plugin-yml


  • ESLint v6.0.0 and above
  • Node.js v12.22.x, v14.17.x, v16.x and above

:book: Usage


Use .eslintrc.* file to configure rules. See also:

Example .eslintrc.js:

module.exports = {
  extends: [
    // add more generic rulesets here, such as:
    // 'eslint:recommended',
  rules: {
    // override/add rules settings here, such as:
    // 'yml/rule-name': 'error'

This plugin provides configs:

  • plugin:yml/base ... Configuration to enable correct YAML parsing.
  • plugin:yml/recommended ... Above, plus rules to prevent errors or unintended behavior.
  • plugin:yml/standard ... Above, plus rules to enforce the common stylistic conventions.
  • plugin:yml/prettier ... Turn off rules that may conflict with Prettier.

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

Parser Configuration

If you have specified a parser, you need to configure a parser for .yaml.

For example, if you are using the "@babel/eslint-parser", configure it as follows:

module.exports = {
  // ...
  extends: ["plugin:yml/standard"],
  // ...
  parser: "@babel/eslint-parser",
  // Add an `overrides` section to add a parser configuration for YAML.
  overrides: [
      files: ["*.yaml", "*.yml"],
      parser: "yaml-eslint-parser",
  // ...

Running ESLint from the command line

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


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

:computer: Editor Integrations

Visual Studio Code

Use the dbaeumer.vscode-eslint extension that Microsoft provides officially.

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

Example .vscode/settings.json:

    "eslint.validate": [

:white_check_mark: Rules

The --fix option on the command line automatically fixes problems reported by rules which have a wrench :wrench: below.
The rules with the following star :star: are included in the config.

YAML Rules

Rule ID Description Fixable RECOMMENDED STANDARD
yml/block-mapping-question-indicator-newline enforce consistent line breaks after ? indicator :wrench: :star:
yml/block-mapping require or disallow block style mappings. :wrench: :star:
yml/block-sequence-hyphen-indicator-newline enforce consistent line breaks after - indicator :wrench: :star:
yml/block-sequence require or disallow block style sequences. :wrench: :star:
yml/indent enforce consistent indentation :wrench: :star:
yml/key-name-casing enforce naming convention to key names
yml/no-empty-document disallow empty document :star: :star:
yml/no-empty-key disallow empty mapping keys :star: :star:
yml/no-empty-mapping-value disallow empty mapping values :star: :star:
yml/no-empty-sequence-entry disallow empty sequence entries :star: :star:
yml/no-tab-indent disallow tabs for indentation. :star: :star:
yml/plain-scalar require or disallow plain style scalar. :wrench: :star:
yml/quotes enforce the consistent use of either double, or single quotes :wrench: :star:
yml/require-string-key disallow mapping keys other than strings
yml/vue-custom-block/no-parsing-error disallow parsing errors in Vue custom blocks :star: :star:

Extension Rules

Rule ID Description Fixable RECOMMENDED STANDARD
yml/flow-mapping-curly-newline enforce consistent line breaks inside braces :wrench: :star:
yml/flow-mapping-curly-spacing enforce consistent spacing inside braces :wrench: :star:
yml/flow-sequence-bracket-newline enforce linebreaks after opening and before closing flow sequence brackets :wrench: :star:
yml/flow-sequence-bracket-spacing enforce consistent spacing inside flow sequence brackets :wrench: :star:
yml/key-spacing enforce consistent spacing between keys and values in mapping pairs :wrench: :star:
yml/no-irregular-whitespace disallow irregular whitespace :star: :star:
yml/no-multiple-empty-lines disallow multiple empty lines :wrench:
yml/sort-keys require mapping keys to be sorted :wrench:
yml/spaced-comment enforce consistent spacing after the # in a comment :wrench: :star:

:rocket: To Do More Verification

Verify using JSON Schema

You can verify using JSON Schema by checking and installing eslint-plugin-json-schema-validator.

Verify the Vue I18n message resource files

You can verify the message files by checking and installing @intlify/eslint-plugin-vue-i18n.

:beers: Contributing

Welcome contributing!

Please use GitHub's Issues/PRs.

Development Tools

  • npm test runs tests and measures coverage.
  • npm run update runs in order to update readme and recommended configuration.

Working With Rules

This plugin uses yaml-eslint-parser for the parser. Check here to find out about AST.

:couple: Related Packages

:lock: License

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