Package detail

markdownlint

DavidAnson2.2mMIT0.37.4

A Node.js style checker and lint tool for Markdown/CommonMark files.

markdown, lint, md, CommonMark, markdownlint

readme

markdownlint

A Node.js style checker and lint tool for Markdown/CommonMark files.

Install

npm install markdownlint --save-dev

Overview

The Markdown markup language is designed to be easy to read, write, and understand. It succeeds - and its flexibility is both a benefit and a drawback. Many styles are possible, so formatting can be inconsistent; some constructs don't work well in all parsers and should be avoided.

markdownlint is a static analysis tool for Node.js with a library of rules to enforce standards and consistency for Markdown files. It was inspired by - and heavily influenced by - Mark Harrison's markdownlint for Ruby. The initial rules, rule documentation, and test cases came from that project.

markdownlint uses the micromark parser and honors the CommonMark specification for Markdown. It additionally supports popular GitHub Flavored Markdown (GFM) syntax like autolinks and tables as well as directives, footnotes, and math syntax - all implemented by micromark extensions.

CLI
- markdownlint-cli command-line interface for Node.js (works with pre-commit)
- markdownlint-cli2 command-line interface for Node.js (works with pre-commit)
GitHub
Editor
Tooling
Ruby
- markdownlint/mdl gem for Ruby

References

The following specifications are considered authoritative in cases of ambiguity:

Demonstration

markdownlint demo, an interactive, in-browser playground for learning and exploring.

Rules / Aliases

MD001 heading-increment - Heading levels should only increment by one level at a time
MD003 heading-style - Heading style
MD004 ul-style - Unordered list style
MD005 list-indent - Inconsistent indentation for list items at the same level
MD007 ul-indent - Unordered list indentation
MD009 no-trailing-spaces - Trailing spaces
MD010 no-hard-tabs - Hard tabs
MD011 no-reversed-links - Reversed link syntax
MD012 no-multiple-blanks - Multiple consecutive blank lines
MD013 line-length - Line length
MD014 commands-show-output - Dollar signs used before commands without showing output
MD018 no-missing-space-atx - No space after hash on atx style heading
MD019 no-multiple-space-atx - Multiple spaces after hash on atx style heading
MD020 no-missing-space-closed-atx - No space inside hashes on closed atx style heading
MD021 no-multiple-space-closed-atx - Multiple spaces inside hashes on closed atx style heading
MD022 blanks-around-headings - Headings should be surrounded by blank lines
MD023 heading-start-left - Headings must start at the beginning of the line
MD024 no-duplicate-heading - Multiple headings with the same content
MD025 single-title/single-h1 - Multiple top-level headings in the same document
MD026 no-trailing-punctuation - Trailing punctuation in heading
MD027 no-multiple-space-blockquote - Multiple spaces after blockquote symbol
MD028 no-blanks-blockquote - Blank line inside blockquote
MD029 ol-prefix - Ordered list item prefix
MD030 list-marker-space - Spaces after list markers
MD031 blanks-around-fences - Fenced code blocks should be surrounded by blank lines
MD032 blanks-around-lists - Lists should be surrounded by blank lines
MD033 no-inline-html - Inline HTML
MD034 no-bare-urls - Bare URL used
MD035 hr-style - Horizontal rule style
MD036 no-emphasis-as-heading - Emphasis used instead of a heading
MD037 no-space-in-emphasis - Spaces inside emphasis markers
MD038 no-space-in-code - Spaces inside code span elements
MD039 no-space-in-links - Spaces inside link text
MD040 fenced-code-language - Fenced code blocks should have a language specified
MD041 first-line-heading/first-line-h1 - First line in a file should be a top-level heading
MD042 no-empty-links - No empty links
MD043 required-headings - Required heading structure
MD044 proper-names - Proper names should have the correct capitalization
MD045 no-alt-text - Images should have alternate text (alt text)
MD046 code-block-style - Code block style
MD047 single-trailing-newline - Files should end with a single newline character
MD048 code-fence-style - Code fence style
MD049 emphasis-style - Emphasis style
MD050 strong-style - Strong style
MD051 link-fragments - Link fragments should be valid
MD052 reference-links-images - Reference links and images should use a label that is defined
MD053 link-image-reference-definitions - Link and image reference definitions should be needed
MD054 link-image-style - Link and image style
MD055 table-pipe-style - Table pipe style
MD056 table-column-count - Table column count
MD058 blanks-around-tables - Tables should be surrounded by blank lines

See Rules.md for more details.

Custom Rules

In addition to built-in rules, custom rules can be used to address project-specific requirements. To find community-developed rules use keyword markdownlint-rule on npm. To implement your own rules, refer to CustomRules.md.

Configuration

Text passed to markdownlint is parsed as Markdown, analyzed, and any issues reported. Two kinds of text are ignored by most rules:

HTML comments
Front matter (see options.frontMatter below)

Rules can be enabled, disabled, and configured via options.config (described below) to define the expected behavior for a set of inputs. To enable or disable rules at a particular location within a file, add one of these markers to the appropriate place (HTML comments don't appear in the final markup):

Disable all rules: 
Enable all rules: 
Disable all rules for the current line: 
Disable all rules for the next line: 
Disable one or more rules by name: 
Enable one or more rules by name: 
Disable one or more rules by name for the current line: 
Disable one or more rules by name for the next line: 
Capture the current rule configuration: 
Restore the captured rule configuration:

For example:

<!-- markdownlint-disable-next-line no-space-in-emphasis -->
space * in * emphasis

Or:

space * in * emphasis <!-- markdownlint-disable-line no-space-in-emphasis -->

Or:

<!-- markdownlint-disable no-space-in-emphasis -->
space * in * emphasis
<!-- markdownlint-enable no-space-in-emphasis -->

To temporarily disable rule(s), then restore the former configuration:

<!-- markdownlint-capture -->
<!-- markdownlint-disable -->
any violations you want
<!-- markdownlint-restore -->

The initial configuration is captured by default (as if every document began with ), so the pattern above can be expressed more simply:

<!-- markdownlint-disable -->
any violations you want
<!-- markdownlint-restore -->

Changes take effect starting with the line a comment is on, so the following has no effect:

space * in * emphasis <!-- markdownlint-disable --> <!-- markdownlint-enable -->

To apply changes to an entire file regardless of where the comment is located, the following syntax is supported:

Disable all rules: 
Enable all rules: 
Disable one or more rules by name: 
Enable one or more rules by name:

This can be used to "hide" markdownlint comments at the bottom of a file.

In cases where it is desirable to change the configuration of one or more rules for a file, the following more advanced syntax is supported:

Configure:

For example:

<!-- markdownlint-configure-file { "hr-style": { "style": "---" } } -->

<!-- markdownlint-configure-file
{
  "hr-style": {
    "style": "---"
  },
  "no-trailing-spaces": false
}
-->

These changes apply to the entire file regardless of where the comment is located. Multiple such comments (if present) are applied top-to-bottom. By default, content of markdownlint-configure-file is assumed to be JSON, but options.configParsers can be used to support alternate formats.

API

Linting

Asynchronous API via import { lint } from "markdownlint/async":

/**
 * Lint specified Markdown files.
 *
 * @param {Options | null} options Configuration options.
 * @param {LintCallback} callback Callback (err, result) function.
 * @returns {void}
 */
function lint(options, callback) { ... }

Synchronous API via import { lint } from "markdownlint/sync":

/**
 * Lint specified Markdown files.
 *
 * @param {Options | null} options Configuration options.
 * @returns {LintResults} Results object.
 */
function lint(options) { ... }

Promise API via import { lint } from "markdownlint/promise":

/**
 * Lint specified Markdown files.
 *
 * @param {Options | null} options Configuration options.
 * @returns {Promise<LintResults>} Results object.
 */
function lint(options) { ... }

options

Type: Object

Configures the function. All properties are optional, but at least one of files or strings should be set to provide input.

options.config

Type: Object mapping String to Boolean | Object

Configures the rules to use.

Object keys are rule names/aliases; object values are the rule's configuration. The value false disables a rule, true enables its default configuration, and passing an object value customizes that rule. Setting the special default rule to true or false includes/excludes all rules by default. In the absence of a configuration object, all rules are enabled. Enabling or disabling a tag name (ex: whitespace) affects all rules having that tag.

The default rule is applied first, then keys are processed in order from top to bottom with later values overriding earlier ones. Keys (including rule names, aliases, tags, and default) are not case-sensitive.

Example:

{
  "default": true,
  "MD003": { "style": "atx_closed" },
  "MD007": { "indent": 4 },
  "no-hard-tabs": false,
  "whitespace": false
}

See .markdownlint.jsonc and/or .markdownlint.yaml for an example configuration object with all properties set to the default value.

Sets of rules (known as a "style") can be stored separately and loaded as JSON.

Example of referencing a built-in style from JavaScript:

const options = {
  "files": [ "..." ],
  "config": require("style/relaxed.json")
};

Example doing so from .markdownlint.json via extends (more on this below):

{
  "extends": "markdownlint/style/relaxed"
}

See the style directory for more samples.

See markdownlint-config-schema.json for the JSON Schema of the options.config object.

See ValidatingConfiguration.md for ways to use the JSON Schema to validate configuration.

For more advanced scenarios, styles can reference and extend other styles. The readConfig and readConfigSync functions can be used to read such styles.

For example, assuming a base.json configuration file:

{
  "default": true
}

And a custom.json configuration file:

{
  "extends": "base.json",
  "line-length": false
}

Then code like the following:

const options = {
  "config": markdownlint.readConfigSync("./custom.json")
};

Merges custom.json and base.json and is equivalent to:

const options = {
  "config": {
    "default": true,
    "line-length": false
  }
};

options.configParsers

Type: Optional Array of Function taking (String) and returning Object

Array of functions to parse the content of markdownlint-configure-file blocks.

As shown in the Configuration section, inline comments can be used to customize the configuration object for a document. By default, the JSON.parse built-in is used, but custom parsers can be specified. Content is passed to each parser function until one returns a value (vs. throwing an exception). As such, strict parsers should come before flexible ones.

For example:

[ JSON.parse, require("toml").parse, require("js-yaml").load ]

options.customRules

Type: Array of Object

List of custom rules to include with the default rule set for linting.

Each array element should define a rule. Rules are typically exported by another package, but can be defined locally.

Example:

const extraRules = require("extraRules");
const options = {
  "customRules": [ extraRules.one, extraRules.two ]
};

See CustomRules.md for details about authoring custom rules.

options.files

Type: Array of String

List of files to lint.

Each array element should be a single file (via relative or absolute path); globbing is the caller's responsibility.

Example: [ "one.md", "dir/two.md" ]

options.frontMatter

Type: RegExp

Matches any front matter found at the beginning of a file.

Some Markdown content begins with metadata; the default RegExp for this option ignores common forms of "front matter". To match differently, specify a custom RegExp or use the value null to disable the feature.

The default value:

/((^---[^\S\r\n\u2028\u2029]*$[\s\S]+?^---\s*)|(^\+\+\+[^\S\r\n\u2028\u2029]*$[\s\S]+?^(\+\+\+|\.\.\.)\s*)|(^\{[^\S\r\n\u2028\u2029]*$[\s\S]+?^\}\s*))(\r\n|\r|\n|$)/m

Ignores YAML, TOML, and JSON front matter such as:

---
layout: post
title: Title
---

Note: Matches must occur at the start of the file.

options.fs

Type: Object implementing the file system API

In advanced scenarios, it may be desirable to bypass the default file system API. If a custom file system implementation is provided, markdownlint will use that instead of using node:fs.

Note: The only methods called are readFile and readFileSync.

options.handleRuleFailures

Type: Boolean

Catches exceptions thrown during rule processing and reports the problem as a rule violation.

By default, exceptions thrown by rules (or the library itself) are unhandled and bubble up the stack to the caller in the conventional manner. By setting handleRuleFailures to true, exceptions thrown by failing rules will be handled by the library and the exception message logged as a rule violation. This setting can be useful in the presence of (custom) rules that encounter unexpected syntax and fail. By enabling this option, the linting process is allowed to continue and report any violations that were found.

options.markdownItPlugins

Type: Array of Array of Function and plugin parameters

Specifies additional markdown-it plugins to use when parsing input. Plugins can be used to support additional syntax and features for advanced scenarios. Deprecated.

Each item in the top-level Array should be of the form:

[ require("markdown-it-plugin"), plugin_param_0, plugin_param_1, ... ]

Note that markdown-it plugins are only called when the markdown-it parser is invoked. None of the built-in rules use the markdown-it parser, so markdown-it plugins will only be invoked when one or more custom rules that use the markdown-it parser are present.

options.noInlineConfig

Type: Boolean

Disables the use of HTML comments like  to toggle rules within the body of Markdown content.

By default, properly-formatted inline comments can be used to create exceptions for parts of a document. Setting noInlineConfig to true ignores all such comments.

options.resultVersion

Type: Number

Specifies which version of the result object to return (see the "Usage" section below for examples).

Passing a resultVersion of 0 corresponds to the original, simple format where each error is identified by rule name and line number. Deprecated

Passing a resultVersion of 1 corresponds to a detailed format where each error includes information about the line number, rule name, alias, description, as well as any additional detail or context that is available. Deprecated

Passing a resultVersion of 2 corresponds to a detailed format where each error includes information about the line number, rule names, description, as well as any additional detail or context that is available. Deprecated

Passing a resultVersion of 3 corresponds to the detailed version 2 format with additional information about how to fix automatically-fixable errors. In this mode, all errors that occur on each line are reported (other versions report only the first error for each rule). This is the default behavior.

options.strings

Type: Object mapping String to String

Map of identifiers to strings for linting.

When Markdown content is not available as files, it can be passed as strings. The keys of the strings object are used to identify each input value in the result summary.

Example:

{
  "readme": "# README\n...",
  "changelog": "# CHANGELOG\n..."
}

callback

Type: Function taking (Error, Object)

Standard completion callback.

result

Type: Object

Call result.toString() for convenience or see below for an example of the structure of the result object. Passing the value true to toString() uses rule aliases (ex: no-hard-tabs) instead of names (ex: MD010).

Config

The options.config configuration object is simple and can be stored in a file for readability and easy reuse. The readConfig and readConfigSync functions load configuration settings and support the extends keyword for referencing other files (see above).

By default, configuration files are parsed as JSON (and named .markdownlint.json). Custom parsers can be provided to handle other formats like JSONC, YAML, and TOML.

Asynchronous API via import { readConfig } from "markdownlint/async":

/**
 * Read specified configuration file.
 *
 * @param {string} file Configuration file name.
 * @param {ConfigurationParser[] | ReadConfigCallback} [parsers] Parsing function(s).
 * @param {Object} [fs] File system implementation.
 * @param {ReadConfigCallback} [callback] Callback (err, result) function.
 * @returns {void}
 */
function readConfig(file, parsers, fs, callback) { ... }

Synchronous API via import { readConfig } from "markdownlint/sync":

/**
 * Read specified configuration file.
 *
 * @param {string} file Configuration file name.
 * @param {ConfigurationParser[]} [parsers] Parsing function(s).
 * @param {Object} [fs] File system implementation.
 * @returns {Configuration} Configuration object.
 */
function readConfig(file, parsers, fs) { ... }

Promise API via import { readConfig } from "markdownlint/promise":

/**
 * Read specified configuration file.
 *
 * @param {string} file Configuration file name.
 * @param {ConfigurationParser[]} [parsers] Parsing function(s).
 * @param {Object} [fs] File system implementation.
 * @returns {Promise<Configuration>} Configuration object.
 */
function readConfig(file, parsers, fs) { ... }

file

Type: String

Location of configuration file to read.

The file is resolved relative to the current working directory. If an extends key is present once read, its value will be resolved as a path relative to file and loaded recursively. Settings from a file referenced by extends are applied first, then those of file are applied on top (overriding any of the same keys appearing in the referenced file). If either the file or extends path begins with the ~ directory, it will act as a placeholder for the home directory.

parsers

Type: Optional Array of Function taking (String) and returning Object

Array of functions to parse configuration files.

The contents of a configuration file are passed to each parser function until one of them returns a value (vs. throwing an exception). Consequently, strict parsers should come before flexible parsers.

For example:

[ JSON.parse, require("toml").parse, require("js-yaml").load ]

fs

Type: Optional Object implementing the file system API

In advanced scenarios, it may be desirable to bypass the default file system API. If a custom file system implementation is provided, markdownlint will use that instead of invoking node:fs.

Note: The only methods called are readFile, readFileSync, access, and accessSync.

callback

Type: Function taking (Error, Object)

Standard completion callback.

result

Type: Object

Configuration object.

Fixing

Rules that can be fixed automatically include a fixInfo property which is outlined in the documentation for custom rules. To apply fixes consistently, the applyFix/applyFixes methods may be used via import { applyFix, applyFixes } from "markdownlint":

/**
 * Applies the specified fix to a Markdown content line.
 *
 * @param {string} line Line of Markdown content.
 * @param {RuleOnErrorFixInfo} fixInfo RuleOnErrorFixInfo instance.
 * @param {string} [lineEnding] Line ending to use.
 * @returns {string | null} Fixed content or null if deleted.
 */
function applyFix(line, fixInfo, lineEnding = "\n") { ... }

/**
 * Applies as many of the specified fixes as possible to Markdown content.
 *
 * @param {string} input Lines of Markdown content.
 * @param {RuleOnErrorInfo[]} errors RuleOnErrorInfo instances.
 * @returns {string} Fixed content.
 */
function applyFixes(input, errors) { ... }

Invoking applyFixes with the results of a call to lint can be done like so:

import { applyFixes } from "markdownlint";
import { lint as lintSync } from "markdownlint/sync";

const results = lintSync({ "strings": { "content": original } });
const fixed = applyFixes(original, results.content);

Miscellaneous

To get the semantic version of the library, the getVersion method can be used:

/**
 * Gets the (semantic) version of the library.
 *
 * @returns {string} SemVer string.
 */
function getVersion() { ... }

Invoking getVersion is simple:

import { getVersion } from "markdownlint";

// Displays the library version
console.log(getVersion());

Usage

Invoke lint and use the result object's toString method:

import { lint as lintAsync } from "markdownlint/async";

const options = {
  "files": [ "good.md", "bad.md" ],
  "strings": {
    "good.string": "# good.string\n\nThis string passes all rules.",
    "bad.string": "#bad.string\n\n#This string fails\tsome rules."
  }
};

lintAsync(options, function callback(error, results) {
  if (!error && results) {
    console.log(results.toString());
  }
});

Output:

bad.string: 3: MD010/no-hard-tabs Hard tabs [Column: 19]
bad.string: 1: MD018/no-missing-space-atx No space after hash on atx style heading [Context: "#bad.string"]
bad.string: 3: MD018/no-missing-space-atx No space after hash on atx style heading [Context: "#This string fails        some rules."]
bad.string: 1: MD041/first-line-heading/first-line-h1 First line in a file should be a top-level heading [Context: "#bad.string"]
bad.md: 3: MD010/no-hard-tabs Hard tabs [Column: 17]
bad.md: 1: MD018/no-missing-space-atx No space after hash on atx style heading [Context: "#bad.md"]
bad.md: 3: MD018/no-missing-space-atx No space after hash on atx style heading [Context: "#This file fails      some rules."]
bad.md: 1: MD041/first-line-heading/first-line-h1 First line in a file should be a top-level heading [Context: "#bad.md"]

Or as a synchronous call:

import { lint as lintSync } from "markdownlint/sync";

const results = lintSync(options);
console.log(results.toString());

To examine the result object directly via a Promise-based call:

import { lint as lintPromise } from "markdownlint/promise";

const results = await lintPromise(options);
console.dir(results, { "colors": true, "depth": null });

Output:

{
  "good.md": [],
  "bad.md": [
    { "lineNumber": 3,
      "ruleNames": [ "MD010", "no-hard-tabs" ],
      "ruleDescription": "Hard tabs",
      "ruleInformation": "https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md010.md",
      "errorDetail": "Column: 17",
      "errorContext": null,
      "errorRange": [ 17, 1 ] },
    { "lineNumber": 1,
      "ruleNames": [ "MD018", "no-missing-space-atx" ],
      "ruleDescription": "No space after hash on atx style heading",
      "ruleInformation": "https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md018.md",
      "errorDetail": null,
      "errorContext": "#bad.md",
      "errorRange": [ 1, 2 ] },
    { "lineNumber": 3,
      "ruleNames": [ "MD018", "no-missing-space-atx" ],
      "ruleDescription": "No space after hash on atx style heading",
      "ruleInformation": "https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md018.md",
      "errorDetail": null,
      "errorContext": "#This file fails\tsome rules.",
      "errorRange": [ 1, 2 ] },
    { "lineNumber": 1,
      "ruleNames": [ "MD041", "first-line-heading", "first-line-h1" ],
      "ruleDescription": "First line in a file should be a top-level heading",
      "ruleInformation": "https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md041.md",
      "errorDetail": null,
      "errorContext": "#bad.md",
      "errorRange": null }
  ]
}

Integration with the gulp build system is straightforward: gulpfile.cjs.

Integration with the Grunt build system is similar: Gruntfile.cjs.

Browser

markdownlint also works in the browser.

Generate normal and minified scripts with:

npm run build-demo

Then reference the markdownlint-browser script:

<script src="demo/markdownlint-browser.min.js"></script>

And call it like so:

const options = {
  "strings": {
    "content": "Some Markdown to lint."
  }
};

const results = globalThis.markdownlint.lintSync(options).toString();

Examples

For ideas how to integrate markdownlint into your workflow, refer to the following projects or one of the tools in the Related section:

.NET Documentation (Search repository)
ally.js (Search repository)
Apache Airflow (Search repository)
Boostnote (Search repository)
CodiMD (Search repository)
Electron (Search repository)
ESLint (Search repository)
Garden React Components (Search repository)
MDN Web Docs (Search repository)
MkDocs (Search repository)
Mocha (Search repository)
Pi-hole documentation (Search repository)
Reactable (Search repository)
V8 (Search repository)
webhint (Search repository)
webpack (Search repository)
WordPress (Search repository)

For more advanced integration scenarios:

Contributing

See CONTRIBUTING.md for more information.

Releasing

See ReleaseProcess.md for more information.

History

See CHANGELOG.md.

changelog

Changelog

0.37.4

Stop using module.createRequire, export resolveModule

0.37.3

Tweak package.json dependencies to work with pnpm

0.37.2

Add subpath imports for overriding default bundler behavior
Improve MD032

0.37.1

Add support for "browser" condition (as used by webpack)

0.37.0

Convert module to ECMAScript (breaking change)
- https://nodejs.org/docs/latest/api/esm.html
- https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c
Convert module to named exports (breaking change)

0.36.1

Fix behavior of MD054

0.36.0

Improve MD051
Move applyFix and applyFixes from helpers to core
Make micromark parser available to custom rules
Introduce ./micromark helpers exports
Update custom/rule documentation
Improve performance
Update dependencies

0.35.0

Add MD058/blanks-around-tables
Use micromark in MD001/MD003/MD009/MD010/MD013/MD014/MD019/MD021/MD023/ MD024/MD025/MD039/MD042/MD043
Improve MD018/MD020/MD031/MD034/MD044
markdown-it parser no longer invoked by default
Add strict version of JSON schema
Improve performance
Update dependencies

0.34.0

Use micromark in MD027/MD028/MD036/MD040/MD041/MD046/MD048
Improve MD013/MD034/MD049/MD050/MD051
Update custom rule requirements and documentation
Improve various TypeScript declarations
Update dependencies

0.33.0

Add MD055/table-pipe-style, MD056/table-column-count
Improve MD005/MD007/MD024/MD026/MD038
Incorporate micromark-extension-directive
Improve JSON schema, document validation
Reduce size of browser script
Update dependencies

0.32.1

Fix behavior of MD054

0.32.0

Remove deprecated MD002/MD006
Remove rule aliases for "header"
Add MD054/link-image-style
Use micromark in MD005/MD007/MD030
Improve MD022/MD026/MD034/MD037/MD038/MD045/MD051
Improve JSON schema and related examples
Provide type declaration for Configuration object
Remove support for end-of-life Node version 16
Update dependencies

0.31.1

Improve MD032/MD034
Update dependencies

0.31.0

Improve MD032/MD037/MD043/MD044/MD051/MD052
Improve performance
Update dependencies

0.30.0

Use micromark in MD022/MD026/MD032/MD037/MD045/MD051
Incorporate micromark-extension-math for math syntax
Allow custom rules to override information URL
Update dependencies

0.29.0

Update micromark parser dependencies for better performance
Use micromark in MD049/MD050
Improve MD034/MD037/MD044/MD049/MD050
Support multiple parsers in demo page
Remove support for end-of-life Node version 14
Update dependencies

0.28.2

Update dependencies for CVE-2023-2251

0.28.1

Update dependencies

0.28.0

Introduce micromark parser for better positional data (internal only)
Use micromark in MD013/MD033/MD034/MD035/MD038/MD044/MD052/MD053
Simplify file-based test cases
Unify browser script for demo page
Update dependencies

0.27.0

Improve MD011/MD013/MD022/MD031/MD032/MD033/MD034/MD040/MD043/MD051/MD053
Generate/separate documentation
Improve documentation
Update dependencies

0.26.2

Improve MD037/MD051/MD053

0.26.1

Improve MD051

0.26.0

Add MD051/MD052/MD053 for validating link fragments & reference links/images & link/image reference definitions (MD053 auto-fixable)
Improve MD010/MD031/MD035/MD039/MD042/MD044/MD049/MD050
Add markdownlint-disable-line inline comment
Support ~ paths in readConfig/Sync
Add configParsers option
Remove support for end-of-life Node version 12
Default resultVersion to 3
Update browser script to use ES2015
Simplify JSON schema
Address remaining CodeQL issues
Improve performance
Update dependencies

0.25.1

Update dependencies for CVE-2022-21670

0.25.0

Add MD049/MD050 for consistent emphasis/strong style (both auto-fixable)
Improve MD007/MD010/MD032/MD033/MD035/MD037/MD039
Support asynchronous custom rules
Improve performance
Improve CI process
Reduce dependencies
Update dependencies

0.24.0

Remove support for end-of-life Node version 10
Add support for custom file system module
Improve MD010/MD011/MD037/MD043/MD044
Improve TypeScript declaration file and JSON schema
Update dependencies

0.23.1

Work around lack of webpack support for dynamic calls to require(.resolve)

0.23.0

Add comprehensive example .markdownlint.jsonc/.markdownlint.yaml files
Add fix information for MD004/ul-style
Improve MD018/MD019/MD020/MD021/MD037/MD041
Improve HTML comment handling
Update test runner and test suite
Update dependencies

0.22.0

Allow extends in config to reference installed packages by name
Add markdownlint-disable-next-line inline comment
Support JSON front matter
Improve MD009/MD026/MD028/MD043
Update dependencies (including markdown-it to v12)

0.21.1

Improve MD011/MD031
Export getVersion API

0.21.0

Lint concurrently for better performance (async only)
Add Promise-based APIs
Update TypeScript declaration file
Hide toString on LintResults
Add ability to fix in browser demo
Allow custom rules in .markdownlint.json schema
Improve MD042/MD044
Improve documentation
Update dependencies

0.20.4

Fix regression in MD037
Improve MD034/MD044
Improve documentation

0.20.3

Fix regression in MD037
Improve MD044
Add automatic regression testing

0.20.2

Fix regression in MD037
Improve MD038

0.20.1

Fix regression in MD037

0.20.0

Add markdownlint-configure-file inline comment
Reimplement MD037
Improve MD005/MD007/MD013/MD018/MD029/MD031/MD034/MD038/MD039
Improve HTML comment handling
Update dependencies

0.19.0

Remove support for end-of-life Node version 8
Add fix information for MD005/list-indent
Improve MD007/MD013/MD014
Deprecate MD006/ul-start-left
Add rationale for every rule
Update test runner and code coverage
Add more JSDoc comments
Update dependencies

0.18.0

Add MD048/code-fence-style
Add fix information for MD007/ul-indent
Add markdownlint-disable-file/markdownlint-enable-file inline comments
Add type declaration file (.d.ts) for TypeScript dependents
Update schema
Improve MD006/MD007/MD009/MD013/MD030
Update dependencies

0.17.2

Improve MD020/MD033/MD044

0.17.1

Fix handling of front matter by fix information

0.17.0

Add resultVersion 3 to support fix information for default and custom rules
Add fix information for 24 rules
Update newline handling to match latest CommonMark specification
Improve MD014/MD037/MD039
Update dependencies

0.16.0

Add custom rule sample for linting code
Improve MD026/MD031/MD033/MD038
Update dependencies

0.15.0

Add markdownlint-capture/markdownlint-restore inline comments
Improve MD009/MD013/MD026/MD033/MD036
Update dependencies

0.14.2

Improve MD047
Add handleRuleFailures option

0.14.1

Improve MD033

0.14.0

Remove support for end-of-life Node version 6
Introduce markdownlint-rule-helpers
Add MD046/MD047
Improve MD033/MD034/MD039
Improve custom rule validation and in-browser demo
Update dependencies

0.13.0

Improve MD013/MD022/MD025/MD029/MD031/MD032/MD037/MD041
Deprecate MD002
Improve Pandoc YAML support
Update dependencies

0.12.0

Add information link for custom rules
Add markdownItPlugins for extensibility
Improve MD023/MD032/MD038
Update dependencies

0.11.0

Improve MD005/MD024/MD029/MD038
Improve custom rule example
Add CONTRIBUTING.md
Update dependencies

0.10.0

Add support for non-JSON configuration files
Pass file/string name to custom rules
Update dependencies

0.9.0

Remove support for end-of-life Node versions 0.10/0.12/4
Change "header" to "heading" per spec (non-breaking)
Improve MD003/MD009/MD041
Handle uncommon line-break characters
Refactor for ES6
Update dependencies

0.8.1

Update item loop to be iterative
Improve MD014
Update dependencies

0.8.0

Add support for using and authoring custom rules
Improve MD004/MD007/MD013
Add engines to package.json
Refactor
Update dependencies

0.7.0

resultVersion defaults to 2 (breaking change)
Add MD045
Improve MD029
Remove trimLeft/trimRight
Split rules
Refactor
Update dependencies

0.6.4

Improve MD029/MD042
Update dependencies

0.6.3

Improve highlighting for MD020

0.6.2

Improve MD013/MD027/MD034/MD037/MD038/MD041/MD044
Update dependencies

0.6.1

Update markdown-it versioning
Exclude demo/test from publishing

0.6.0

resultVersion defaults to 1 (breaking change)
Ignore HTML comments
TOML front matter
Fixes for MD044
Update dependencies

0.5.0

Add shareable configuration
Add noInlineConfig option
Add README.md links
Fix MD030
Improve MD009/MD041
Update dependencies

0.4.1

Fixes for MD038/front matter
Improvements to MD044
Update dependencies

0.4.0

Add MD044
Enhance MD013/MD032/MD041/MD042/MD043
Fix for MD038
Update dependencies

0.3.1

Fix regressions in MD032/MD038
Update dependencies

0.3.0

More detailed error reporting with resultVersion
Enhance MD010/MD012/MD036
Fixes for MD027/MD029/MD030
Include JSON schema dependencies

0.2.0

Add MD042/MD043
Enhance MD002/MD003/MD004/MD007/MD011/MD025/MD041
Update dependencies

0.1.1

Fix bug handling HTML in tables
Reference markdownlint-cli

0.1.0

Add aliases
Exceptions for MD033
Exclusions for MD013
Update dependencies

0.0.8

Support disabling/enabling rules inline
Improve code fence
Update dependencies

0.0.7

Add MD041
Improve MD003
Ignore front matter
Update dependencies

0.0.6

Improve performance
Simplify in-browser
Update dependencies

0.0.5

Add strings option to enable file-less scenarios
Add in-browser demo

0.0.4

Add tests MD033-MD040
Update dependencies

0.0.3

Add synchronous API
Improve documentation and code

0.0.2

Improve documentation, tests, and code

0.0.1

Initial release
Includes tests MD001-MD032

Package detail

readme

markdownlint

Install

Overview

Related

References

Demonstration

Rules / Aliases

Custom Rules

Tags

Configuration

API

Linting

options

options.config

options.configParsers

options.customRules

options.files

options.frontMatter

options.fs

options.handleRuleFailures

options.markdownItPlugins

options.noInlineConfig

options.resultVersion

options.strings

callback

result

Config

file

parsers

fs

callback

result

Fixing

Miscellaneous

Usage

Browser

Examples

Contributing

Releasing

History

changelog

Changelog

0.37.4

0.37.3

0.37.2

0.37.1

0.37.0

0.36.1

0.36.0

0.35.0

0.34.0

0.33.0

0.32.1

0.32.0

0.31.1

0.31.0

0.30.0

0.29.0

0.28.2

0.28.1

0.28.0

0.27.0

0.26.2

0.26.1

0.26.0

0.25.1

0.25.0

0.24.0

0.23.1

0.23.0

0.22.0

0.21.1

0.21.0

0.20.4

0.20.3

0.20.2

0.20.1

0.20.0