green-pass-simple/js/my_base45_2.js

function encode(uint8array) {
  var output = [];

  for (var i = 0, length = uint8array.length; i < length; i += 2) {
    if (uint8array.length - i > 1) {
      var x = (uint8array[i] << 8) + uint8array[i + 1]
      var [e, x] = divmod(x, 45 * 45)
      var [d, c] = divmod(x, 45)
      output.push(fromCharCode(c) + fromCharCode(d) + fromCharCode(e))
    } else {
      var x = uint8array[i]
      var [d, c] = divmod(x, 45)
      output.push(fromCharCode(c) + fromCharCode(d))
    }
  }
  return output.join('')
};

var divmod = function divmod(a, b) {
  var remainder = a
  var quotient = 0
  if (a >= b) {
    remainder = a % b
    quotient = (a - remainder) / b
  }
  return [quotient, remainder]
}

const BASE45_CHARSET = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ $%*+-./:"
var fromCharCode = function fromCharCode(c) {
  return BASE45_CHARSET.charAt(c);
};

function decode(str) {
  var output = []
  var buf = []

  for (var i = 0, length = str.length; i < length; i++) {
    //console.log(i);
    var j = BASE45_CHARSET.indexOf(str[i])
    if (j < 0)
      console.log('Base45 decode: unknown character n.', i, j);
    //throw new Error('Base45 decode: unknown character');
    buf.push(j)
  }

  for (var i = 0, length = buf.length; i < length; i += 3) {
    var x = buf[i] + buf[i + 1] * 45
    if (length - i >= 3) {
      var [d, c] = divmod(x + buf[i + 2] * 45 * 45, 256)
      output.push(d)
      output.push(c)
    } else {
      output.push(x)
    }
  }
  console.log("output", output);
  var enc = new TextEncoder();
  return { "enc": enc.encode(output), "raw": output };
  //return Buffer.from(output);
};