How to use the @hapi/b64.base64urlDecode function in @hapi/b64

if (request.method !== 'GET' &&
        request.method !== 'HEAD') {

        throw Utils.unauthorized('Invalid method');
    }

    // No other authentication

    if (request.authorization) {
        throw Boom.badRequest('Multiple authentications');
    }

    // Parse bewit

    try {
        var bewitString = B64.base64urlDecode(resource[3]);
    }
    catch (err) {
        throw Boom.badRequest('Invalid bewit encoding');
    }

    // Bewit format: id\exp\mac\ext ('\' is used because it is a reserved header attribute character)

    const bewitParts = bewitString.split('\\');
    if (bewitParts.length !== 4) {
        throw Boom.badRequest('Invalid bewit structure');
    }

    const bewit = {
        id: bewitParts[0],
        exp: parseInt(bewitParts[1], 10),
        mac: bewitParts[2],

password = internals.normalizePassword(password);

    // Check hmac

    const macOptions = Hoek.clone(options.integrity);
    macOptions.salt = hmacSalt;
    const mac = await exports.hmacWithPassword(password.integrity, macOptions, macBaseString);

    if (!Cryptiles.fixedTimeComparison(mac.digest, hmac)) {
        throw new Boom.Boom('Bad hmac value');
    }

    // Decrypt

    try {
        var encrypted = B64.base64urlDecode(encryptedB64, 'buffer');
    }
    catch (err) {
        throw Boom.boomify(err);
    }

    const decryptOptions = Hoek.clone(options.encryption);
    decryptOptions.salt = encryptionSalt;

    try {
        decryptOptions.iv = B64.base64urlDecode(encryptionIv, 'buffer');
    }
    catch (err) {
        throw Boom.boomify(err);
    }

    const decrypted = await exports.decrypt(password.encryption, decryptOptions, encrypted);

}

    // Decrypt

    try {
        var encrypted = B64.base64urlDecode(encryptedB64, 'buffer');
    }
    catch (err) {
        throw Boom.boomify(err);
    }

    const decryptOptions = Hoek.clone(options.encryption);
    decryptOptions.salt = encryptionSalt;

    try {
        decryptOptions.iv = B64.base64urlDecode(encryptionIv, 'buffer');
    }
    catch (err) {
        throw Boom.boomify(err);
    }

    const decrypted = await exports.decrypt(password.encryption, decryptOptions, encrypted);

    // Parse JSON

    try {
        return Bourne.parse(decrypted);
    }
    catch (err) {
        throw new Boom.Boom('Failed parsing sealed object JSON: ' + err.message);
    }
};