# @markuplint/types > Type declaration and value checker Latest version **5.0.1** (published 2026-09-22) · MIT license · 0 weekly downloads ## Install ```sh npm install @markuplint/types pnpm add @markuplint/types yarn add @markuplint/types bun add @markuplint/types ``` ## Health **Score 65/100 (B)** — status: active. Positive: esm support; no vulnerabilities; has provenance; recently updated; high maintenance score. Warnings: low downloads; no types. ## Facts | | | |---|---| | Version | 5.0.1 | | Published | 2026-09-22 | | First published | 2021-12-12 | | Weekly downloads | 0 | | License | MIT | | TypeScript types | none | | Module format | ESM | | Node | >=24 | | Dependencies | 10 | | Unpacked size | 431.2 KB | | Known vulnerabilities | 0 | | Install scripts | no | | Provenance | attested (GitHub Actions) | | GitHub stars | 617 | | Author | Yusuke Hirao | | Maintainers | yusukehirao | ## Links - npm: https://www.npmjs.com/package/@markuplint/types - Repository: https://github.com/markuplint/markuplint - Homepage: https://github.com/markuplint/markuplint#readme - Issues: https://github.com/markuplint/markuplint/issues - npm.io page: https://npm.io/package/@markuplint/types ## Dependencies (10) - [debug](https://npm.io/package/debug.md) 4.4.3 - [leven](https://npm.io/package/leven.md) 4.1.0 - [bcp-47](https://npm.io/package/bcp-47.md) 2.1.0 - [css-tree](https://npm.io/package/css-tree.md) 3.2.1 - [type-fest](https://npm.io/package/type-fest.md) 5.6.0 - [@types/debug](https://npm.io/package/@types/debug.md) 4.1.13 - [@types/css-tree](https://npm.io/package/@types/css-tree.md) 2.3.11 - [whatwg-mimetype](https://npm.io/package/whatwg-mimetype.md) 5.0.0 - [@markuplint/shared](https://npm.io/package/@markuplint/shared.md) 5.0.1 - [language-subtag-registry](https://npm.io/package/language-subtag-registry.md) 0.4.2 ## Recent versions - 5.0.1 (latest) — 2026-09-22 - 5.0.0-rc.7 (rc) — 2026-08-31 - 5.0.0-rc.1 (next) — 2026-03-27 - 5.0.0-dev.5 (canary) — 2026-02-27 - 3.0.0-alpha.27 (dev) — 2022-12-20 - 5.0.0 — 2026-09-11 - 5.0.0-rc.6 — 2026-08-30 - 5.0.0-rc.5 — 2026-08-29 - 4.18.0 — 2026-04-22 - 5.0.0-rc.4 — 2026-04-19 - 5.0.0-rc.2 — 2026-04-15 - 5.0.0-rc.0 — 2026-03-12 - 5.0.0-alpha.3 — 2026-02-26 - 5.0.0-alpha.2 — 2026-02-23 - 5.0.0-alpha.1 — 2026-02-22 - … 119 more at https://npm.io/package/@markuplint/types/versions ## README # @markuplint/types [![npm version](https://badge.fury.io/js/%40markuplint%2Ftypes.svg)](https://www.npmjs.com/package/@markuplint/types) **Type declaration and value checker** ## Type declaration - [types.schema.json](./types.schema.json) ## API ```ts import { check } from '@markuplint/types'; check('2020-01-01', 'DateTime'); // => { matched: true } check('2020-02-30', 'DateTime'); // => { // matched: false, // reason: { type: 'out-of-range', gte: 1, lte: 29 }, // expects: [], // partName: 'date', // ref: 'https://html.spec.whatwg.org/multipage/text-level-semantics.html#datetime-value', // raw: '30', // offset: 8, // length: 2, // line: 1, // column: 9, // } ``` ### `checkBase` Validates a value against a type definition object (enum, list, number, directive, or keyword type). ```ts import { checkBase } from '@markuplint/types'; checkBase('hello', { enum: ['hello', 'world'] }, {}); // => { matched: true } ``` ### `isCustomElementName` Checks whether a string is a valid custom element name according to the WHATWG specification. ```ts import { isCustomElementName } from '@markuplint/types'; isCustomElementName()('my-element'); // => true isCustomElementName()('div'); // => false ``` ### Type Exports The package also exports the following types: | Type | Description | | --------------------- | ---------------------------------------------------------- | | `Result` | Union type of `MatchedResult` and `UnmatchedResult` | | `MatchedResult` | Represents a successful match (`{ matched: true }`) | | `UnmatchedResult` | Represents a failed match with location and reason details | | `Type` | Union of all type definition shapes (enum, list, etc.) | | `Defs` | Registry mapping type identifiers to their definitions | | `CustomSyntaxChecker` | Factory function type for creating value checkers | ## Type Identifiers | Identifier | Use on | Spec | Supported | | ---------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------ | --------- | | `Any` | Some attributes | | ✅ | | `NoEmptyAny` | Some attributes | | ✅ | | `OneLineAny` | Some attributes | | ✅ | | `Zero` | Some attributes | | ✅ | | `Number` | Some attributes | | ✅ | | `Uint` | Some attributes | | ✅ | | `JSON` | Attributes on some frameworks etc. | | ✅ | | `XMLName` | `svg\|[attributeName]` and more | [XML](https://www.w3.org/TR/xml/#d0e804) | ✅ | | `DOMID` | The `id` attribute and more | [WHATWG](https://html.spec.whatwg.org/multipage/dom.html#global-attributes:concept-id) | ✅ | | `FunctionBody` | Event handler attributes | | 🚧 | | `Pattern` | `input[pattern]` | [WHATWG](https://html.spec.whatwg.org/multipage/input.html#compiled-pattern-regular-expression) | ✅ | | `DateTime` | `time[datetime]` and more | [WHATWG](https://html.spec.whatwg.org/multipage/text-level-semantics.html#datetime-value) | ✅ | | `DateStringWithOptionalTime` | `del[datetime]`, `ins[datetime]` | [WHATWG](https://html.spec.whatwg.org/multipage/edits.html#attr-mod-datetime) | ✅ | | `DateString` | `input[value]` when `type=date` | [WHATWG](https://html.spec.whatwg.org/multipage/common-microsyntaxes.html#dates) | ✅ | | `TimeString` | `input[value]` when `type=time` | [WHATWG](https://html.spec.whatwg.org/multipage/common-microsyntaxes.html#times) | ✅ | | `MonthString` | `input[value]` when `type=month` | [WHATWG](https://html.spec.whatwg.org/multipage/common-microsyntaxes.html#months) | ✅ | | `WeekString` | `input[value]` when `type=week` | [WHATWG](https://html.spec.whatwg.org/multipage/common-microsyntaxes.html#weeks) | ✅ | | `LocalDateTimeString` | `input[value]` when `type=datetime-local` | [WHATWG](https://html.spec.whatwg.org/multipage/common-microsyntaxes.html#local-dates-and-times) | ✅ | | `SimpleColor` | `input[value]` when `type=color` | [WHATWG](https://html.spec.whatwg.org/multipage/common-microsyntaxes.html#valid-simple-colour) | ✅ | | `Email` | `input[value]` when `type=email` | [WHATWG](https://html.spec.whatwg.org/multipage/input.html#valid-e-mail-address) | ✅ | | `TabIndex` | The `tabindex` attribute | [WHATWG](https://html.spec.whatwg.org/multipage/interaction.html#attr-tabindex) | ✅ | | `BCP47` | The `lang` attribute and more | [RFC](https://tools.ietf.org/rfc/bcp/bcp47.html) | ✅ | | `URL` | `a[href]`, `area[href]`, `blockquote[cite]`, `del[cite]`, `ins[cite]`, `q[cite]` and more (every URL-typed attribute that does **not** require a non-empty value) | [WHATWG](https://html.spec.whatwg.org/multipage/urls-and-fetching.html#valid-url-potentially-surrounded-by-spaces) | ✅ | | `NonEmptyURL` | `audio[src]`, `button[formaction]`, `embed[src]`, `form[action]`, `iframe[src]`, `img[src]`, `input[formaction]`, `input[type=image][src]`, `link[href]`, `object[data]`, `script[src]`, `source[src]`, `track[src]`, `video[poster]`, `video[src]` | [WHATWG](https://html.spec.whatwg.org/multipage/urls-and-fetching.html#valid-non-empty-url-potentially-surrounded-by-spaces) | ✅ | | `BaseURL` | `base[href]` | [WHATWG](https://html.spec.whatwg.org/multipage/semantics.html#set-the-frozen-base-url) | ✅ | | `AbsoluteURL` | The `itemtype` attribute (as list) | [WHATWG](https://url.spec.whatwg.org/#syntax-url-absolute) | ✅ | | `AbsoluteURLOrEmpty` | `input[type=url][value]` | [WHATWG]() | ✅ | | `HashName` | `img[usemap]` | [WHATWG](https://html.spec.whatwg.org/multipage/common-microsyntaxes.html#valid-hash-name-reference) | ✅ | | `OneCodePointChar` | The `accesskey` attribute (as list) | [WHATWG](https://html.spec.whatwg.org/multipage/interaction.html#the-accesskey-attribute) | ✅ | | `CustomElementName` | The `is` attribute | [WHATWG](https://html.spec.whatwg.org/multipage/custom-elements.html#valid-custom-element-name) | ✅ | | ~~`BrowsingContextName`~~ | Use `NavigableTargetName` instead. | **Obsoleted** | ✅ | | ~~`BrowsingContextNameOrKeyword`~~ | Use `NavigableTargetNameOrKeyword` instead. | **Obsoleted** | ✅ | | `NavigableTargetName` | `iframe[name]` and more | [WHATWG](https://html.spec.whatwg.org/multipage/document-sequences.html#valid-navigable-target-name) | ✅ | | `NavigableTargetNameOrKeyword` | `a[target]` and more | [WHATWG](https://html.spec.whatwg.org/multipage/document-sequences.html#valid-navigable-target-name-or-keyword) | ✅ | | `HTTPSchemaURL` | `a[ping]` (as list) and more | [WHATWG](https://html.spec.whatwg.org/multipage/links.html#ping) | ✅ | | `MIMEType` | `embed[type]` and more | [WHATWG](https://mimesniff.spec.whatwg.org/#valid-mime-type) | ✅ | | `MediaQueryList` | `link[media]`, `style[media]`, `source[media]`, `svg\|style[media]` | [W3C](https://www.w3.org/TR/mediaqueries-5/#mq-features) | ✅ | | `HTTPEquivRefresh` | `meta[content]` when `http-equiv=refresh` | [WHATWG](https://html.spec.whatwg.org/multipage/semantics.html#attr-meta-http-equiv-refresh) | ✅ | | `HTTPEquivContentType` | `meta[content]` when `http-equiv=content-type` | [WHATWG](https://html.spec.whatwg.org/multipage/semantics.html#attr-meta-http-equiv-content-type) | ✅ | | `ContentSecurityPolicy` | `meta[content]` when `http-equiv=content-security-policy` | [W3C](https://www.w3.org/TR/CSP3/#framework-policy) | ✅ | | `ItemProp` | The `itemprop` attribute (as list) | [WHATWG](https://html.spec.whatwg.org/multipage/microdata.html#names:-the-itemprop-attribute) | ✅ | | `Srcset` | `img[srcset]` and more | [WHATWG](https://html.spec.whatwg.org/multipage/images.html#srcset-attributes) | ✅ | | `SourceSizeList` | `img[sizes]` and more | [WHATWG](https://html.spec.whatwg.org/multipage/images.html#sizes-attributes) | ✅ | | `IconSize` | `link[sizes]` (as list) | [WHATWG](https://html.spec.whatwg.org/multipage/semantics.html#attr-link-sizes) | ✅ | | `AutoComplete` | `input[autocomplete]` and more | [WHATWG](https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#attr-fe-autocomplete) | ✅ | | `Accept` | `input[accept]` | [WHATWG](https://html.spec.whatwg.org/multipage/input.html#attr-input-accept) | ✅ | | `SerializedPermissionsPolicy` | `iframe[allow]` | [W3C](https://w3c.github.io/webappsec-permissions-policy/#serialized-permissions-policy) | ✅ | | `LinkTypeForLinkElement` | `link[rel]` | [WHATWG](https://html.spec.whatwg.org/multipage/links.html#linkTypes) [microformats](https://microformats.org/wiki/existing-rel-values) | ✅ | | `LinkTypeForLinkElementInBody` | `link[rel]` in `` | [WHATWG](https://html.spec.whatwg.org/multipage/links.html#body-ok) [microformats](https://microformats.org/wiki/existing-rel-values#HTML5_link_type_extensions) | ✅ | | `LinkTypeForAnchorAndAreaElement` | `a[rel]`, `area[rel]` | [WHATWG](https://html.spec.whatwg.org/multipage/links.html#linkTypes) [microformats](https://microformats.org/wiki/existing-rel-values#HTML5_link_type_extensions) | ✅ | | `LinkTypeForFormElement` | `form[rel]` | [WHATWG](https://html.spec.whatwg.org/multipage/links.html#linkTypes) [microformats](https://microformats.org/wiki/existing-rel-values#HTML5_link_type_extensions) | ✅ | | `` | The `style` attribute | [CSS](https://drafts.csswg.org/css-style-attr/#syntax) | ✅ | | `` | The `class` attribute | [SVG](https://www.w3.org/TR/SVG/styling.html#ClassAttribute) | ✅ | | `` | Some attributes for SVG | [CSS](https://drafts.csswg.org/css-fonts-5/#descdef-font-face-font-size) | 🚧 | | `` | Some attributes for SVG | [CSS](https://drafts.csswg.org/css-fonts-5/#propdef-font-size-adjust) | 🚧 | | `<'color-profile'>` | Some attributes for SVG | [SVG](https://www.w3.org/TR/SVG11/color.html#ColorProfileProperty) | 🚧 | | `<'color-rendering'>` | Some attributes for SVG | [SVG](https://www.w3.org/TR/SVG11/painting.html#ColorRenderingProperty) | 🚧 | | `<'enable-background'>` | Some attributes for SVG | [SVG](https://www.w3.org/TR/SVG11/filters.html#EnableBackgroundProperty) | 🚧 | | `` | Some attributes for SVG | [SVG](https://www.w3.org/TR/SVG11/feature.html) | 🚧 | | `` | Some attributes for SVG | [SVG](https://svgwg.org/specs/animations/#FromAttribute) | 🚧 | | `` | Some attributes for SVG | [SVG](https://svgwg.org/specs/animations/#BeginValueListSyntax) | 🚧 | | `` | Some attributes for SVG | [SVG](https://svgwg.org/specs/animations/#EndValueListSyntax) | 🚧 | | `` | Some attributes for SVG | [SVG](https://svgwg.org/specs/animations/#ValuesAttribute) | 🚧 | | `` | Some attributes for SVG | [SMIL](https://www.w3.org/TR/2001/REC-smil-animation-20010904/#Timing-ClockValueSyntax) | 🚧 | | `` | Some attributes for SVG | [W3C](https://drafts.fxtf.org/filter-effects/#element-attrdef-fecolormatrix-values) | ✅ | | `` | Some attributes for SVG | [SVG](https://svgwg.org/svg2-draft/painting.html#StrokeDasharrayProperty) | ✅ | | `` | Some attributes for SVG | [SVG](https://svgwg.org/specs/animations/#KeyPointsAttribute) | ✅ | | `` | Some attributes for SVG | [SVG](https://svgwg.org/specs/animations/#KeyTimesAttribute) | ✅ | | `` | Some attributes for SVG | [SVG](https://svgwg.org/specs/animations/#KeyTimesAttribute) | ✅ | | `` | Some attributes for SVG | [SVG](https://svgwg.org/svg2-draft/struct.html#SystemLanguageAttribute) | ✅ | | `` | Some attributes for SVG | [SMIL](https://www.w3.org/TR/2001/REC-smil-animation-20010904/#MotionOriginAttribute) | ✅ | | `` | Some attributes for SVG | [SVG](https://svgwg.org/svg2-draft/paths.html#PathDataBNF) | 🚧 | | `` | Some attributes for SVG | [SVG](https://svgwg.org/svg2-draft/shapes.html#DataTypePoints) | ✅ | | `` | Some attributes for SVG | [SVG](https://svgwg.org/svg2-draft/coords.html#PreserveAspectRatioAttribute) | ✅ | | `` | Some attributes for SVG | [SVG](https://svgwg.org/svg2-draft/coords.html#ViewBoxAttribute) | ✅ | | `` | Some attributes for SVG | [SVG](https://svgwg.org/specs/animations/#RotateAttribute) | ✅ | | `` | Some attributes for SVG | [SVG](https://svgwg.org/svg2-draft/text.html#TSpanAttributes) | ✅ | | `` | Some attributes for SVG | | ✅ | | `` | Some attributes for SVG | | ✅ | | `` | Some attributes for SVG | | ✅ | | `` | Some attributes for SVG | | ✅ | In addition, you can use types **[CSSTree](https://github.com/csstree/csstree)** defined. ## Install ```shell $ npm install @markuplint/types $ yarn add @markuplint/types ``` --- _Source: https://npm.io/package/@markuplint/types · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._