cssauron

build a matching function in CSS for any nested object structure without eval

Usage

Import

Common JS

From version v2.0.0, cssauron will only support ES6 modules. In order to import cssauron with NodeJS versions prior v12, you may use esm.

Import default

import cssauron from '@gofunky/cssauron'

const language = cssauron({
  tag: 'tagName',
  contents: 'innerText',
  id: 'id',
  class: 'className',
  parent: 'parentNode',
  children: 'childNodes',
  attr: 'getAttribute(attr)'
})

const selector = language('body > #header .logo')
const element = document.getElementsByClassName('logo')[0]

if(selector(element)) {
  // element matches selector
} else {
  // element does not match selector
}

Import as class

import { CSSAuron } from '@gofunky/cssauron'

const language = new CSSAuron({})
const selector = language.parse('body > #header .logo')

Constructor options

options are an object hash of lookup type to string attribute or function(node) lookups for queried nodes. You only need to provide the configuration necessary for the selectors you're planning on creating. (If you're not going to use #id lookups, there's no need to provide the id lookup in your options.)

• tag: Extract tag information from a node for div style selectors.
• contents: Extract text information from a node, for :contains(xxx) selectors.
• id: Extract id for #my_sweet_id selectors.
• class: .class_name
• parent: Used to traverse up from the current node, for composite selectors body #wrapper, body > #wrapper.
• children: Used to traverse from a parent to its children for sibling selectors div + span, a ~ p.
• attr: Used to extract attribute information, for [attr=thing] style selectors.

language('some selector') -> match function

Compiles a matching function.

match(node) -> false | node | [subjects, ...]

Returns false if the provided node does not match the selector. Returns true if the provided node does match. The exact return value is determined by the selector, based on the CSS4 subject selector spec: If only a single node matches, only this node is returned. If multiple subjects match, a deduplicated array of those subjects is returned.

For example, given the following HTML:

<div id="gary-busey">
    <p>
        <span class="jake-busey">
        </span>
    </p>
</div>

Checking the following selectors against the span.jake-busey element yield:

• #gary-busey: false, no match.
• #gary-busey *: span.jake-busey, a single match.
• !#gary-busey *: div#gary-busey, a single match using the ! subject selector.
• #gary-busey *, p span: span.jake-busey, a single match, though both selectors match.
• #gary-busey !* !*, !p > !span: [p, span.jake-busey], two matches.

Supported pseudo-classes

• :first-child
• :last-child
• :nth-child
• :empty
• :root
• :contains(text)
• :any(selector, selector, selector)

Supported attribute lookups

• [attr=value]: Exact match
• [attr]: Attribute exists and is not false-y.
• [attr$=value]: Attribute ends with value
• [attr^=value]: Attribute starts with value
• [attr*=value]: Attribute contains value
• [attr~=value]: Attribute, split by whitespace, contains value.
• [attr|=value]: Attribute, split by -, contains value.