luhn-generator/update/node_modules/axe-core/lib/commons/text/label-text.js

A generator of numbers that passes the validation of Luhn algorithm or Luhn formula, also known as the 'modulus 10' or 'mod 10' algorithm

import accessibleTextVirtual from './accessible-text-virtual';
import accessibleText from './accessible-text';
import findElmsInContext from '../dom/find-elms-in-context';
import { closest, nodeSorter } from '../../core/utils';

/**
 * Return accessible text for an implicit and/or explicit HTML label element
 * @param {VirtualNode} element
 * @param {Object} context
 * @property {Bool} inControlContext
 * @property {Bool} inLabelledByContext
 * @return {String} Label text
 */
function labelText(virtualNode, context = {}) {
	const { alreadyProcessed } = accessibleTextVirtual;
	if (
		context.inControlContext ||
		context.inLabelledByContext ||
		alreadyProcessed(virtualNode, context)
	) {
		return '';
	}
	if (!context.startNode) {
		context.startNode = virtualNode;
	}

	const labelContext = { inControlContext: true, ...context };
	const explicitLabels = getExplicitLabels(virtualNode);
	const implicitLabel = closest(virtualNode, 'label');

	let labels;
	if (implicitLabel) {
		labels = [...explicitLabels, implicitLabel.actualNode];
		labels.sort(nodeSorter);
	} else {
		labels = explicitLabels;
	}

	return labels
		.map(label => accessibleText(label, labelContext))
		.filter(text => text !== '')
		.join(' ');
}

/**
 * Find a non-ARIA label for an element
 * @private
 * @param {VirtualNode} element The VirtualNode instance whose label we are seeking
 * @return {HTMLElement} The label element, or null if none is found
 */
function getExplicitLabels(virtualNode) {
	if (!virtualNode.attr('id')) {
		return [];
	}

	if (!virtualNode.actualNode) {
		throw new TypeError(
			'Cannot resolve explicit label reference for non-DOM nodes'
		);
	}

	return findElmsInContext({
		elm: 'label',
		attr: 'for',
		value: virtualNode.attr('id'),
		context: virtualNode.actualNode
	});
}

export default labelText;