PleaseNo.php

<?php

declare(strict_types=1);

namespace Zegnat;

final class PleaseNo
{
    /**
     * Returns a DOM element’s text content as if the DOM had been rendered through an
     * approximate implementation of the HTML specification’s innerText getter.
     *
     * @see https://html.spec.whatwg.org/#dom-innertext
     **/
    public function innerText(\DOMElement $element): string
    {
        if ($this->isBeingRendered($element) === false) {
            return $element->textContent;
        }
        $count = 0;
        $output = '';
        foreach ($this->innerTextCollectionSteps($element) as $item) {
            if ($output !== '' && is_int($item) && $item > $count) {
                $count = $item;
            } elseif (is_string($item) && $item !== '') {
                $output .= str_repeat("\n", $count) . $item;
                $count = 0;
            }
        }
        return $output;
    }

    /**
     * Check if a DOM node should be rendered per section 14 Rendering of the HTML
     * specification. If a node’s `display` value is none, it is not being rendered.
     *
     * For non-Element nodes it is assumed they use whatever value the closest Element
     * parent is using.
     *
     * @TODO Decide if noscript elements are rendered.
     * @TODO Decide if elements that represent nothing (e.g. template) are rendered.
     * @TODO Check if any parent elements are not being rendered, as this cascades down.
     *
     * @see https://html.spec.whatwg.org/#hidden-elements 14.3.1 Hidden elements
     * @see https://html.spec.whatwg.org/#tables-2        14.3.9 Tables
     **/
    private function isBeingRendered(\DOMNode $element): bool
    {
        // When this runs on a non-Element, walk up the tree to the closest element.
        while (!$element instanceof \DOMElement) {
            $element = $element->parentNode;
        }
        // List of elements that always have `display: none`.
        $elements = ['area', 'base', 'basefont', 'datalist', 'head', 'link', 'meta',
            'noembed', 'noframes', 'param', 'rp', 'script', 'source', 'style', 'template',
            'track', 'title'];
        // List of elements that are still rendered with the hidden attribute set.
        $exceptions = ['embed', 'colgroup', 'col', 'thead', 'tbody', 'tfoot', 'tr', 'td',
            'th'];
        // List of parents that stop a form element from rendering.
        $form = ['table', 'thead', 'tbody', 'tfoot', 'tr'];
        // Figure it out!
        $name = strtolower($element->tagName);
        return !(in_array($name, $elements) ||
            $element->hasAttribute('hidden') && !in_array($name, $exceptions) ||
            $name === 'input' && strtolower($element->getAttribute('type')) === 'hidden' ||
            $name === 'form' && in_array(strtolower($element->parentNode->tagName), $form));
    }

    /**
     * @TODO Implement.
     *
     * @see https://html.spec.whatwg.org/#inner-text-collection-steps
     **/
    private function innerTextCollectionSteps(\DOMNode $node): array
    {
        
    }
}