An extremely simple implementation of base64 encoding / decoding using node.js Buffers (plus url-safe versions)

base64.js

/*
 * base64.js: An extremely simple implementation of base64 encoding / decoding using node.js Buffers
 *
 * (C) 2010, Nodejitsu Inc.
 * (C) 2011, Cull TV, Inc.
 *
 */

var base64 = exports;

base64.encode = function(unencoded) {
  return new Buffer(unencoded || '').toString('base64');
};

base64.decode = function(encoded) {
  return new Buffer(encoded || '', 'base64').toString('utf8');
};

base64.urlEncode = function(unencoded) {
  var encoded = base64.encode(unencoded);
  return encoded.replace(/\+/g, '-').replace(/\//g, '_').replace(/=+$/, '');
};

base64.urlDecode = function(encoded) {
  encoded = encoded.replace(/-/g, '+').replace(/_/g, '/');
  while (encoded.length % 4)
    encoded += '=';
  return base64.decode(encoded);
};

thanks :)

For ASCII only use cases:

function encode(textToEncode) {
  return btoa(textToEncode).replace(/\+/g, '~').replace(/\//g, '_').replace(/=/g, '-');
}

function decode(textToDecode: string): string {
  return atob(textToDecode.replace(/~/g, '+').replace(/_/g, '/').replace(/-/g, '='));
}