axe-core/lib/rules/color-contrast-matches.js

Accessibility engine for automated Web UI testing

/* global document */

var nodeName = node.nodeName.toUpperCase(),
	nodeType = node.type;

if (node.getAttribute('aria-disabled') === 'true' ||
	axe.commons.dom.findUpVirtual(virtualNode, '[aria-disabled="true"]')) {
	return false;
}

if (nodeName === 'INPUT') {
	return ['hidden', 'range', 'color', 'checkbox', 'radio', 'image'].indexOf(nodeType) === -1 && !node.disabled;
}

if (nodeName === 'SELECT') {
	return !!node.options.length && !node.disabled;
}

if (nodeName === 'TEXTAREA') {
	return !node.disabled;
}

if (nodeName === 'OPTION') {
	return false;
}

if (nodeName === 'BUTTON' && node.disabled ||
	axe.commons.dom.findUpVirtual(virtualNode, 'button[disabled]')) {
	return false;
}

if (nodeName === 'FIELDSET' && node.disabled ||
	axe.commons.dom.findUpVirtual(virtualNode, 'fieldset[disabled]')) {
	return false;
}

// check if the element is a label or label descendant for a disabled control
var nodeParentLabel = axe.commons.dom.findUpVirtual(virtualNode, 'label');
if (nodeName === 'LABEL' || nodeParentLabel) {
	var relevantNode = node;
	var relevantVirtualNode = virtualNode;

	if (nodeParentLabel) {
		relevantNode = nodeParentLabel;
		// we need an input candidate from a parent to account for label children
		relevantVirtualNode = axe.utils.getNodeFromTree(axe._tree[0], nodeParentLabel);
	}
	// explicit label of disabled input
	let doc = axe.commons.dom.getRootNode(relevantNode);
	var candidate = relevantNode.htmlFor && doc.getElementById(relevantNode.htmlFor);
	if (candidate && candidate.disabled) {
		return false;
	}

	var candidate = axe.utils.querySelectorAll(relevantVirtualNode, 'input:not([type="hidden"]):not([type="image"])' +
		':not([type="button"]):not([type="submit"]):not([type="reset"]), select, textarea');
	if (candidate.length && candidate[0].actualNode.disabled) {
		return false;
	}

}

// label of disabled control associated w/ aria-labelledby
if (node.getAttribute('id')) {
	const id = axe.commons.utils.escapeSelector(node.getAttribute('id'));
	let doc = axe.commons.dom.getRootNode(node);
	var candidate = doc.querySelector('[aria-labelledby~=' + id + ']');
	if (candidate && candidate.disabled) {
		return false;
	}
}

if (axe.commons.text.visibleVirtual(virtualNode, false, true) === '') {
	return false;
}

var range = document.createRange(),
	childNodes = virtualNode.children,
	length = childNodes.length,
	child, index;

for (index = 0; index < length; index++) {
	child = childNodes[index];

	if (child.actualNode.nodeType === 3 && axe.commons.text.sanitize(child.actualNode.nodeValue) !== '') {
		range.selectNodeContents(child.actualNode);
	}
}

var rects = range.getClientRects();
length = rects.length;

for (index = 0; index < length; index++) {
	//check to see if the rectangle impinges
	if (axe.commons.dom.visuallyOverlaps(rects[index], node)) {
		return true;
	}
}

return false;