+++ /dev/null
-/* @flow */
-"use strict";
-
-const htmlTags = require("html-tags");
-const keywordSets = require("../reference/keywordSets");
-const mathMLTags = require("mathml-tag-names");
-const svgTags = require("svg-tags");
-
-/**
- * Check whether a type selector is a custom element
- */
-module.exports = function(selector /*: string*/) /*: boolean*/ {
- if (!/^[a-z]/.test(selector)) {
- return false;
- }
-
- if (selector.indexOf("-") === -1) {
- return false;
- }
-
- const selectorLowerCase = selector.toLowerCase();
-
- if (selectorLowerCase !== selector) {
- return false;
- }
- if (svgTags.indexOf(selectorLowerCase) !== -1) {
- return false;
- }
- if (htmlTags.indexOf(selectorLowerCase) !== -1) {
- return false;
- }
- if (keywordSets.nonStandardHtmlTags.has(selectorLowerCase)) {
- return false;
- }
- if (mathMLTags.indexOf(selectorLowerCase) !== -1) {
- return false;
- }
-
- return true;
-};