How to use the eosjs.Numeric.publicKeyToString function in eosjs

throw new Error('Public key is not EC2');
    if (pubKey.get(3) !== -7)
        throw new Error('Public key is not ES256');
    if (pubKey.get(-1) !== 1)
        throw new Error('Public key has unsupported curve');
    const x = pubKey.get(-2);
    const y = pubKey.get(-3);
    if (x.length !== 32 || y.length !== 32)
        throw new Error('Public key has invalid X or Y size');
    const ser = new Serialize.SerialBuffer({textEncoder: new util.TextEncoder(), textDecoder: new util.TextDecoder()});
    ser.push((y[31] & 1) ? 3 : 2);
    ser.pushArray(x);
    ser.push(flagsToPresence(flags));
    ser.pushString(k.rpid);
    const compact = ser.asUint8Array();
    const key = Numeric.publicKeyToString({
        type: Numeric.KeyType.wa,
        data: compact,
    });
    console.log({
        flags: ('00' + flags.toString(16)).slice(-2),
        signCount,
        aaguid,
        credentialIdLength,
        credentialId: Serialize.arrayToHex(credentialId),
        rpid: k.rpid,
        presence: flagsToPresence(flags),
        x: Serialize.arrayToHex(x),
        y: Serialize.arrayToHex(y),
        compact: Serialize.arrayToHex(compact),
        key,
    });