declare module 'base-64' {
  declare module.exports: {
   version: string,
   /**
    * This function takes a byte string (the input parameter) and encodes it according to base64.
    * The input data must be in the form of a string containing only characters
    * in the range from U+0000 to U+00FF, each representing a binary byte with values 0x00 to 0xFF.
    * The base64.encode() function is designed to be fully compatible
    * with btoa() as described in the HTML Standard.
    * see: https://html.spec.whatwg.org/multipage/webappapis.html#dom-windowbase64-btoa
    */
   encode(input: string): string,
   /**
    * This function takes a base64-encoded string (the input parameter) and decodes it.
    * The return value is in the form of a string containing only characters in
    * the range from U+0000 to U+00FF, each representing a binary byte with values 0x00 to 0xFF.
    * The base64.decode() function is designed to be fully compatible
    * with atob() as described in the HTML Standard.
    * see: https://html.spec.whatwg.org/multipage/webappapis.html#dom-windowbase64-atob
    */
   decode(input: string): string,
   ...
  };
}
