| 1234567891011121314151617181920212223242526272829303132333435363738394041 | 'use strict';const { htmlTypeSelectors } = require('../reference/selectors');const mathMLTags = require('mathml-tag-names');const svgTags = require('svg-tags');/** * Check whether a type selector is a custom element * * @param {string} selector * @returns {boolean} */module.exports = function isCustomElement(selector) {	if (!/^[a-z]/.test(selector)) {		return false;	}	if (!selector.includes('-')) {		return false;	}	const selectorLowerCase = selector.toLowerCase();	if (selectorLowerCase !== selector) {		return false;	}	if (svgTags.includes(selectorLowerCase)) {		return false;	}	if (htmlTypeSelectors.has(selectorLowerCase)) {		return false;	}	if (mathMLTags.includes(selectorLowerCase)) {		return false;	}	return true;};
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