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cssauron

build a matching function in CSS for any nested object structure!

var language = require('cssauron')({
tag: 'tagName'
, contents: 'innerText'
, id: 'id'
, class: 'className'
, parent: 'parentNode'
, children: 'childNodes'
, attr: 'getAttribute(attr)'
})
var selector = language('body > #header .logo')
, element = document.getElementsByClassName('logo')[0]
if(selector(element)) {
// element matches selector
} else {
// element does not match selector
}

It's easy to use with your favorite nested tree structures! Delicious with HTML! Digestable with JSON!

HTML | JSON | GLSL AST | JS AST (Esprima)
--- | --- | --- | ---
cssauron-html | cssauron-json | cssauron-glsl | cssauron-falafel

# API

### require('cssauron')(options) -> selector factory

Import `cssauron` and configure it for the nested object structure you'll want to match against.

#### 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.

### selector_factory('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 truthy if the provided node does match. Exact return value is determined by the selector, based on the CSS4 subject selector spec: if only a single node is matched, only that node is returned. If multiple subjects are matched, a deduplicated array of those subjects are returned.

For example, given the following HTML (and `cssauron-html`):

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

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

- `#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 pseudoclasses

- `: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.