Issue on FueAuth

[carlhussey]

I am using FuelSoap with FuelAuth and running into an issue on setting up the client.

var FuelAuthClient = new FuelAuth({
    clientId: clientId,
    clientSecret: clientSecret,
    authUrl: authOrigin,
    authOptions: {
        authVersion: 2
    }
});

FuelAuthClient.getAccessToken()
    .then(function (data) {
        // data.accessToken = your token
        // data.expiresIn = how long until token expiration
        console.log(data);

        var SoapClient = new FuelSoap(FuelAuthClient);

        SoapClient.retrieve(
            'Email',
            ["ID", "Name", "Subject", "CategoryID", "EmailType"],
            options,
            function (err, response) {
                if (err) {
                    // error here
                    console.log(err);
                    return;
                }

                // response.body === parsed soap response (JSON)
                // response.res === full response from request client
                console.log(response.body);
            }


        )
    })
    .catch(function (err) {
        console.log(err);
    });

The issue I am facing is in the FuelSoap initialization where it checks to see if its an instance of FuelAuth.

	var authOptions = options && options.auth || {};

	// use fuel auth instance if applicable
	if(authOptions instanceof  FuelAuth) {
		this.AuthClient = authOptions;
	} else {
		try {
			this.AuthClient = new FuelAuth(authOptions);
		} catch (err) {
			throw err;
		}
	}```

It looks like this line `var authOptions = options && options.auth || {};` is creating an empty object, expecting that `options.auth` exists. Well, when using the `FuelAuth` object, thats not the case so it defaults `authOptions = {}`.

This causes the `if(authOptions instanceof  FuelAuth) {` to return false and it tries to initialize `FuelAuth` using the `authOptions` which is an empty object. This throws an error in `FuelAuth`  about `Error: clientId or clientSecret is missing or invalid`.

To summarize, `if(authOptions instanceof  FuelAuth) {` returns false when using `FuelAuth` because `options.auth` doesn't exist which causes `authOptions` to be set to an empty object.