Function _parseConfig

src/purify.ts:720–1028

(cfg: Config = {})

   */
  // eslint-disable-next-line complexity
  const _parseConfig = function (cfg: Config = {}): void {
    if (CONFIG && CONFIG === cfg) {
      return;
    }

    /* Shield configuration object from tampering */
    if (!cfg || typeof cfg !== 'object') {
      cfg = {};
    }

    /* Shield configuration object from prototype pollution */
    cfg = clone(cfg);

    PARSER_MEDIA_TYPE =
      // eslint-disable-next-line unicorn/prefer-includes
      SUPPORTED_PARSER_MEDIA_TYPES.indexOf(cfg.PARSER_MEDIA_TYPE) === -1
        ? DEFAULT_PARSER_MEDIA_TYPE
        : cfg.PARSER_MEDIA_TYPE;

    // HTML tags and attributes are not case-sensitive, converting to lowercase. Keeping XHTML as is.
    transformCaseFunc =
      PARSER_MEDIA_TYPE === 'application/xhtml+xml'
        ? stringToString
        : stringToLowerCase;

    /* Set configuration parameters */
    ALLOWED_TAGS = _resolveSetOption(
      cfg,
      'ALLOWED_TAGS',
      DEFAULT_ALLOWED_TAGS,
      { transform: transformCaseFunc }
    );
    ALLOWED_ATTR = _resolveSetOption(
      cfg,
      'ALLOWED_ATTR',
      DEFAULT_ALLOWED_ATTR,
      { transform: transformCaseFunc }
    );
    ALLOWED_NAMESPACES = _resolveSetOption(
      cfg,
      'ALLOWED_NAMESPACES',
      DEFAULT_ALLOWED_NAMESPACES,
      { transform: stringToString }
    );
    URI_SAFE_ATTRIBUTES = _resolveSetOption(
      cfg,
      'ADD_URI_SAFE_ATTR',
      DEFAULT_URI_SAFE_ATTRIBUTES,
      { transform: transformCaseFunc, base: DEFAULT_URI_SAFE_ATTRIBUTES }
    );
    DATA_URI_TAGS = _resolveSetOption(
      cfg,
      'ADD_DATA_URI_TAGS',
      DEFAULT_DATA_URI_TAGS,
      { transform: transformCaseFunc, base: DEFAULT_DATA_URI_TAGS }
    );
    FORBID_CONTENTS = _resolveSetOption(
      cfg,