Nodejs Utililty Methods String to Ascii85 Convert

String.prototype.toAscii85 = function() {
  var str = this, result = ''
  while (str.length) {
    let num = 0, j = 5, i = 4
    if (str.substr(0,4) == '\u0000\u0000\u0000\u0000') result += 'z'
    else {
      while (i--) {
        num += (str.charCodeAt(3-i) || 0)*Math.pow(2, 8*i)
      while (j-- && str.length > 3-j) {
        result += String.fromCharCode(num/Math.pow(85, j) % 85 + 33)
    str = str.substr(4)
  return `<~${result}~>`

String.prototype.toAscii85 = function() {
  var ret = "";
  for(var i=0; i<this.length; i+=4){
    var deficit = Math.max(0, 4+i-this.length);
    var nnn = 0;
    for(var j=0; j<4; j++){
      nnn = nnn*256 + (this.charCodeAt(i+j) || 0);
    var codes = [];
...

String.prototype.toAscii85 = function() {
  var str = '';
  for(var i = 0, len = this.length; i < len; i+=4) {
    var bin = '';
    var zeroes = 0;
    for(var j = 0; j < 4; j++) {
      var char = this[i+j];
      bin += to8bit(char ? char.charCodeAt(0) : (zeroes++, 0));
    var n = parseInt(bin, 2);
    for(var j = 4; j >= 0; j--) {
      var c = Math.floor(n / Math.pow(85, j));
      n -= c*Math.pow(85, j);
      str += String.fromCharCode(c + 33);
    str = str.slice(0, zeroes > 0 ? -zeroes : undefined);
  return '<~' + str.replace(/!{5}/g, 'z') + '~>'

String.prototype.toAscii85 = function() {
    let pad = '\0', addnum = 0, str = this, res = '', sum = 0;
    while (str.length % 4 !== 0)
        str += pad;
        addnum ++;
    for (let i = 0; i < str.length; i += 4)
        let e = '';
        let temp = str.substr(i, 4);
        for (let j = 0; j < 4; j++)
            let t = temp[j].charCodeAt().toString(2)
            while (t.length !== 8)
                t = '0' + t;
            e += t;
        sum = parseInt(e, 2);
        let encode = [];
        for (let j = 0; j < 5; j++)
            encode.push(0);
        for (let j = 4; j >= 0; j--)
            encode[j] = sum % 85;
            sum = Math.floor(sum / 85);
        for (let j = 0; j < 5; j++)
            res += String.fromCharCode(encode[j] + 33);
    res = res.substr(0, res.length - addnum);
    let newres = '', i = 0;
    for (i = 0; i < res.length; i += 5)
        newres += res.substr(i, Math.min(5, res.length - i)) === '!!!!!' ? 'z' : res.substr(i, Math.min(5, res.length - i));
    return '<~' + newres + '~>';
};