property-information

Info on the properties and attributes of the web platform (HTML, SVG, ARIA, XML, XMLNS, XLink).

Contents

• What is this?
• When should I use this?
• Install
• Use
• API
  • find(schema, name)
  • normalize(name)
  • html
  • svg
  • hastToReact
• Types
• Compatibility
• Support
• Security
• Related
• Contribute
• License

What is this?

This package contains lots of info on all the properties and attributes found on the web platform. It includes data on HTML, SVG, ARIA, XML, XMLNS, and XLink. The names of the properties follow hast’s sensible naming scheme. It includes info on what data types attributes hold, such as whether they’re booleans or contain lists of space separated numbers.

When should I use this?

You can use this package if you’re working with hast, which is an AST for HTML, or have goals related to ASTs, such as figuring out which properties or attributes are valid, or what data types they hold.

Install

This package is ESM only. In Node.js (version 14.14+, 16.0+), install with npm:

npm install property-information

In Deno with esm.sh:

import * as propertyInformation from 'https://esm.sh/property-information@6'

In browsers with esm.sh:

<script type="module">
  import * as propertyInformation from 'https://esm.sh/property-information@6?bundle'
</script>

Use

import {html, svg, find, normalize} from 'property-information'

console.log(find(html, 'className'))
// Or: find(html, 'class')
console.log(find(svg, 'horiz-adv-x'))
// Or: find(svg, 'horizAdvX')
console.log(find(svg, 'xlink:arcrole'))
// Or: find(svg, 'xLinkArcRole')
console.log(find(html, 'xmlLang'))
// Or: find(html, 'xml:lang')
console.log(find(html, 'ariaValueNow'))
// Or: find(html, 'aria-valuenow')

Yields:

{space: 'html', attribute: 'class', property: 'className', spaceSeparated: true}
{space: 'svg', attribute: 'horiz-adv-x', property: 'horizAdvX', number: true}
{space: 'xlink', attribute: 'xlink:arcrole', property: 'xLinkArcrole'}
{space: 'xml', attribute: 'xml:lang', property: 'xmlLang'}
{attribute: 'aria-valuenow', property: 'ariaValueNow', number: true}

API

This package exports the identifiers html, svg, find, normalize, and hastToReact. There is no default export.

find(schema, name)

Look up info on a property.

In most cases, the given schema contains info on the property. All standard, most legacy, and some non-standard properties are supported. For these cases, the returned Info has hints about the value of the property.

name can also be a valid data attribute or property, in which case an Info object with the correctly cased attribute and property is returned.

name can be an unknown attribute, in which case an Info object with attribute and property set to the given name is returned. It is not recommended to provide unsupported legacy or recently specced properties.

Parameters

• schema (Schema) — either the html or svg export
• name (string) — an attribute-like or property-like name that is passed through normalize to find the correct info

Returns

Info.

Example

Aside from the aforementioned example, which shows known HTML, SVG, XML, XLink, and ARIA support, data properties, and attributes are also supported:

console.log(find(html, 'data-date-of-birth'))
// Or: find(html, 'dataDateOfBirth')
// => {attribute: 'data-date-of-birth', property: 'dataDateOfBirth'}

Unknown values are passed through untouched:

console.log(find(html, 'un-Known'))
// => {attribute: 'un-Known', property: 'un-Known'}

normalize(name)

Get the cleaned case insensitive form of an attribute or property.

Parameters

• name (string) — an attribute-like or property-like name

Returns

string that can be used to look up the properly cased property on a Schema.

Example

html.normal[normalize('for')] // => 'htmlFor'
svg.normal[normalize('VIEWBOX')] // => 'viewBox'
html.normal[normalize('unknown')] // => undefined
html.normal[normalize('accept-charset')] // => 'acceptCharset'

html

svg

Schema for either HTML or SVG, containing info on properties from the primary space (HTML or SVG) and related embedded spaces (ARIA, XML, XMLNS, XLink).

Example

console.log(html.property.htmlFor)
// => {space: 'html', attribute: 'for', property: 'htmlFor' spaceSeparated: true}
console.log(svg.property.viewBox)
// => {space: 'svg', attribute: 'viewBox', property: 'viewBox'}
console.log(html.property.unknown)
// => undefined

Schema

A schema for a primary space.

• space ('html' or 'svg') — primary space of the schema
• normal (Record<string, string>) — object mapping normalized attributes and properties to properly cased properties
• property (Record<string, Info>) — object mapping properties to info

Info

Info on a property.

• space ('html', 'svg', 'xml', 'xlink', 'xmlns', optional) — space of the property
• attribute (string) — attribute name for the property that could be used in markup (for example: 'aria-describedby', 'allowfullscreen', 'xml:lang', 'for', or 'charoff')
• property (string) — JavaScript-style camel-cased name, based on the DOM, but sometimes different (for example: 'ariaDescribedBy', 'allowFullScreen', 'xmlLang', 'htmlFor', 'charOff')
• boolean (boolean) — the property is a boolean (for example: hidden). These properties have an on state when defined and an off state when not defined
• booleanish (boolean) — the property is like a boolean (for example: draggable) These properties have both an on and off state when defined, and another state when not defined
• overloadedBoolean (boolean) — the property is like a boolean (for example: download) These properties have an on state plus more states when defined and an off state when not defined
• number (boolean) — the property is a number (for example: height)
• spaceSeparated (boolean) — the property is a list separated by spaces (for example: className)
• commaSeparated (boolean) — the property is a list separated by commas (for example: srcSet)
• commaOrSpaceSeparated (boolean) — the property is a list separated by spaces or commas (for example: strokeDashArray)
• mustUseProperty (boolean) — useful when working with the DOM, in which case this property has to be changed as a field on the element, rather than through setAttribute (this is true only for 'checked', 'multiple', 'muted', and 'selected')
• defined (boolean) — the property is defined by a space. This is true for values in HTML (including data and ARIA), SVG, XML, XMLNS, and XLink. Undefined properties can only be found through find

hastToReact

hast is close to React, but differs in a couple of cases. To get a React property from a hast property, check if it is in hastToReact (Record<string, string>), if it is, then use the corresponding value, otherwise, use the hast property.

Types

This package is fully typed with TypeScript. It exports the additional types Info and Schema.

Compatibility

This package is at least compatible with all maintained versions of Node.js. As of now, that is Node.js 14.14+ and 16.0+. It also works in Deno and modern browsers.

Support

Security

This package is safe.

Related

• wooorm/web-namespaces — list of web namespaces
• wooorm/space-separated-tokens — parse/stringify space separated tokens
• wooorm/comma-separated-tokens — parse/stringify comma separated tokens
• wooorm/html-tag-names — list of HTML tag names
• wooorm/mathml-tag-names — list of MathML tag names
• wooorm/svg-tag-names — list of SVG tag names
• wooorm/html-void-elements — list of void HTML tag names
• wooorm/svg-element-attributes — map of SVG elements to allowed attributes
• wooorm/html-element-attributes — map of HTML elements to allowed attributes
• wooorm/aria-attributes — list of ARIA attributes

Contribute

Yes please! See How to Contribute to Open Source.

License

MIT © Titus Wormer

Derivative work based on React licensed under MIT, © Facebook, Inc.