determineType(input) {
    var url;
    var path;
    var extension;

    if (this.settings.encoding === "base64") {
      return INPUT_TYPE.BASE64;
    }

    if (typeof input != "string") {
      return INPUT_TYPE.BINARY;
    }

    url = new utils_url["a" /* default */](input);
    path = url.path();
    extension = path.extension; // If there's a search string, remove it before determining type

    if (extension) {
      extension = extension.replace(/\?.*$/, "");
    }

    if (!extension) {
      return INPUT_TYPE.DIRECTORY;
    }

    if (extension === "epub") {
      return INPUT_TYPE.EPUB;
    }

    if (extension === "opf") {
      return INPUT_TYPE.OPF;
    }

    if (extension === "json") {
      return INPUT_TYPE.MANIFEST;
    }
  }
Determine the type of they input passed to open
@private
@param  {string} input
@return {string}  binary | directory | epub | opf