creating a did:key and document, also see multibase vs base64url_universal (npm) vs base64url (npm)

gistfile1.txt

const multicodec = require('multicodec')
const multibase = require('multibase')
const toString = require('uint8arrays/to-string')
const fromString = require('uint8arrays/from-string')
const base64url = require('base64url'); // this converts a text string to base64url, it does not take a uint8 array??
const base64url_universal = require('base64url-universal');

const publicKeyHex = 'f9c36f8964623378bdc068d4bce07ed17c8fa486f9ac0c2613ca3c8c306d7bb61cd36717b8ac5e4fea8ad23dc8d0783c2318ee4ad7a80db6e0026ad0b072a24f'


const didKey = publicHexKeyToDIDKey(publicKeyHex);

console.log(didKey);

const KeyBase58 = publickeyToBase58btc(publicKeyHex);

console.log(KeyBase58);

publicKeyToXY(publicKeyHex);

console.log(base64url.encode("hello"));
console.log(base64url_universal.encode("hello"));

function publicHexKeyToDIDKey(publicKeyHex) {
  const publicKey = fromString(publicKeyHex,'base16');
  const publicKeywPrefix = multicodec.addPrefix('p256-pub',publicKey)
  const buf = multibase.encode('base58btc',publicKeywPrefix)
  const bufAsString = toString(buf)
  return `did:key:${bufAsString}`
}

function publickeyToBase58btc(publicKeyHex) {
  const publicKey = fromString(publicKeyHex,'base16');
  const buf = multibase.encode('base58btc',publicKey)
  const buftoString = toString(buf);
  return buftoString;
}

function publicKeyToXY(publicKeyHex) {
   console.log(publicKeyHex.length);
   const xHex = publicKeyHex.slice(0,publicKeyHex.length/2);
   const yHex = publicKeyHex.slice(publicKeyHex.length/2,publicKeyHex.length);
   console.log(publicKeyHex);
   console.log(xHex);
   console.log(yHex);
   xOctet = fromString(xHex,'base16');
   yOctet = fromString(yHex,'base16');
//   console.log('the xOctet is:'+toString(xOctet)+'\n');
//   console.log('the yOctet is:'+toString(yOctet)+'\n');
   xm = toString(multibase.encode('base64url',xOctet));
   ym = toString(multibase.encode('base64url',yOctet));
   xu = base64url_universal.encode(xOctet);
   yu = base64url_universal.encode(yOctet);
   x = base64url.encode(xOctet);
   y = base64url.encode(yOctet);
   console.log('base64url using multibase: '+xm);
   console.log('base64url using b64urluni:  '+xu);
   console.log('base64url using b64url   :  '+x);
   console.log('base64url using multibase: '+ym);
   console.log('base64url using b64urluni:  '+yu);
   console.log('base64url using b64url   :  '+y);
}

output:

did:key:zruuPojWkzGPb8sVc42f2YxcTXKUTpAUbdrzVovaTBmGGNyK6cGFaA4Kp7SSLKecrxYz8Sc9d77Rss7rayYt1oFCaNJ
z5zdNaYFHfgJ5tMm6BReioHKbpZBMxGW1znc1vnWd3P78R3rPcqwUpHx5wRqTJa94xyxJryZUAH5yyGRJZLCkUFNE
128
f9c36f8964623378bdc068d4bce07ed17c8fa486f9ac0c2613ca3c8c306d7bb61cd36717b8ac5e4fea8ad23dc8d0783c2318ee4ad7a80db6e0026ad0b072a24f
f9c36f8964623378bdc068d4bce07ed17c8fa486f9ac0c2613ca3c8c306d7bb6
1cd36717b8ac5e4fea8ad23dc8d0783c2318ee4ad7a80db6e0026ad0b072a24f
base64url using multibase: u-cNviWRiM3i9wGjUvOB-0XyPpIb5rAwmE8o8jDBte7Y
base64url using b64urluni: -cNviWRiM3i9wGjUvOB-0XyPpIb5rAwmE8o8jDBte7Y
base64url using multibase: uHNNnF7isXk_qitI9yNB4PCMY7krXqA224AJq0LByok8
base64url using b64urluni: HNNnF7isXk_qitI9yNB4PCMY7krXqA224AJq0LByok8

https://github.com/digitalbazaar/base64url-universal
https://www.npmjs.com/package/base64url-universal

did:key:zruuPojWkzGPb8sVc42f2YxcTXKUTpAUbdrzVovaTBmGGNyK6cGFaA4Kp7SSLKecrxYz8Sc9d77Rss7rayYt1oFCaNJ

const doc = await ceramic.createDocument({
metadata: {
controllers: ['did:key:zruuPojWkzGPb8sVc42f2YxcTXKUTpAUbdrzVovaTBmGGNyK6cGFaA4Kp7SSLKecrxYz8Sc9d77Rss7rayYt1oFCaNJ'],
// secp256r1 did:key
family: '3id'
},
content: {
publicKeys: {
" ": " ", // secp256r1 public key
// The value of this property should be an object where the value is a multicodec + multibase(base58btc) encoded public key, the key for any // given key should be the last 15 characters of the encoded public key.
}
},
deterministic: true
})

const didString = did:3:${doc.id}