tree-selector

build a matching or query function for CSS selectors for any nested object structure!

import { createQuerySelector, createMatches } from 'tree-selector';

const options = {
    tag: n => n.tagName,
    contents: n => n.innerText,
    id: n => n.id,
    class: n => n.className,
    parent: n => n.parentElement,
    children: n => n.childNodes,
    attr: (n, attr) => n.getAttribute(attr)
};

const querySelector = createQuerySelector(options);
const matches = createMatches(options);

const selector = 'span.mySpan';
const element = document.getElementsByClassName('span')[0]

if(matches(selector, element)) {
  // there are elements matching the selector
} else {
  // no elements found
}

//Also possible, but less efficient
if(querySelector(selector, element).length > 0) {
    // there are elements found
}

API

createQuerySelector(options) -> querySelector

Configure tree-selector for the nested object structure you'll want to match against.

createMatches(options) -> matches

Configure a matches function for a node in your tree structure. (This is used internally by createQuerySelector)

options

options are an object of lookup functions 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 for sibling selectors
• 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.

Supported pseudoclasses

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

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.