Function _isBasicCustomElement

src/purify.ts:2428–2433

(tagName: string)

   * @returns Returns true if the tag name meets the basic criteria for a custom element, otherwise false.
   */
  const _isBasicCustomElement = function (tagName: string): boolean {
    return (
      !RESERVED_CUSTOM_ELEMENT_NAMES[stringToLowerCase(tagName)] &&
      regExpTest(CUSTOM_ELEMENT, tagName)
    );
  };

  /**
   * Wrap an attribute value in the matching Trusted Types object when