Portable and compact JavaScript base32 encoding/decoding functions that I found on the internet

base32_decode.js

function decode(s) {
  const len = s.length;
  const apad = 'abcdefghijklmnopqrstuvwxy1234567z';
  let v,x,r=0,bits=0,c,o='';

  s = s.toUpperCase();

  for(i=0;i<len;i+=1) {
    v = apad.indexOf(s.charAt(i));
    if (v>=0 && v<32) {
      x = (x << 5) | v;
      bits += 5;
      if (bits >= 8) {
        c = (x >> (bits - 8)) & 0xff;
        o = o + String.fromCharCode(c);
        bits -= 8;
      }
    } else {
      return false;
    }
  }
  if (bits>0) {
    c = ((x << (8 - bits)) & 0xff) >> (8 - bits);

    if (c!==0) {
      o = o + String.fromCharCode(c);
    }
  }
  return o;
}

base32_encode.js

function encode (s) {
  const a = 'abcdefghijklmnopqrstuvwxy1234567';
  const pad = 'z';
  const len = s.length;
  let o = '';
  let w, c, r=0, sh=0;
  for(let i=0; i<len; i+=5) {
    c = s.charCodeAt(i);
    w = 0xf8 & c;
    o += a.charAt(w>>3);
    r = 0x07 & c;
    sh = 2;

    if ((i+1)<len) {
      c = s.charCodeAt(i+1);
      w = 0xc0 & c;
      o += a.charAt((r<<2) + (w>>6));
      o += a.charAt( (0x3e & c) >> 1 );
      r = c & 0x01;
      sh = 4;
    }

    if ((i+2)<len) {
      c = s.charCodeAt(i+2);
      w = 0xf0 & c;
      o += a.charAt((r<<4) + (w>>4));
      r = 0x0f & c;
      sh = 1;
    }

    if ((i+3)<len) {
      c = s.charCodeAt(i+3);
      w = 0x80 & c;
      o += a.charAt((r<<1) + (w>>7));
      o += a.charAt((0x7c & c) >> 2);
      r = 0x03 & c;
      sh = 3;
    }

    if ((i+4)<len) {
      c = s.charCodeAt(i+4);
      w = 0xe0 & c;
      o += a.charAt((r<<3) + (w>>5));
      o += a.charAt(0x1f & c);
      r = 0;
      sh = 0;
    }
  }

  if (sh != 0) { o += a.charAt(r<<sh); }

  const padlen = 8 - (o.length % 8);

  if (padlen==8) { return o; }
  if (padlen==1) { return o + pad; }
  if (padlen==3) { return o + pad + pad + pad; }
  if (padlen==4) { return o + pad + pad + pad + pad; }
  if (padlen==6) { return o + pad + pad + pad + pad + pad + pad; }
  return false;
}