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);
};

Your line is also incorrect, as you missed the "g" for the last two replacements :)

encoded.replace(/\+/g, '-').replace(/\//g, '_').replace(/=+$/g, '');

I don't know that it's needed for the last one as the + is greedy, but it shoudln't hurt

Thanks @netzmensch, encoded.replace(/\+/g, '-').replace(/\//g, '_').replace(/=+$/g, ''); seems to work nicely.

The 'g' replacing '=' is not needed, the are equals only at the end of the string. But really useful implementation :)

Thanks @netzmensch, encoded.replace(/\+/g, '-').replace(/\//g, '_').replace(/=+$/g, ''); seems to work nicely.

is work.

The decode function is also missing global "-" and "_" replacement.

Line 25 should be: encoded = encoded.replace(/-/g, '+').replace(/_/g, '/');.

Humans can I present the following for your critique.
I offer this as the replace function
'e8/51e2fa+4f/00+4609+9d/d2+9b3794c/59619====='.replace(/(\+)|(\/)|(=+$)/g,(match) => Object.create({'+': '-', '/': '_', '=': ''})[match[0]])
outputs e8_51e2fa-4f_00-4609-9d_d2-9b3794c_59619

@Rudiger86 nice! might be faster since it only walks through the string once.

I think I got it slightly simplified to:

'e8/51e2fa+4f/00+4609+9d/d2+9b3794c/59619====='.replace(/[+/=]/g, match => 
  ({'+': '-', '/': '_', '=': ''}[match])
)

This is slightly less robust because I replace every =, but hey, in normal base64 strings =es should only ever be at the end anyway.

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, '='));
}