allow non-user dependent requests

[xxzefgh]

What do you think about this change?
https://github.com/sarkestudio/fitbit-node/blob/master/fitbit-api-client.js#L26-L31
I can make a PR if it makes sense.

[nurseybushc]

When would you not pass userId?

[xxzefgh]

food api has several endpoints where you don't need user

[jmdiego]

What about, instead of requiring userId as false, or setting it as default, just check if it's falsy and do:

getUrl(path, userId){
    return `https://api.fitbit.com/${this.apiVersion}${userId ? `/user/${userId}` : ''}${path}`;
}

[xxzefgh]

@jmdiego That would be a breaking change, current implementation automatically inserts - if you don't pass userId, which is useful

[jmdiego]

@thisdotvoid you are right, what about:

getUrl(path, userId){
    let userSubPath = userId === false ? '' : `/user/${userId || '-'}`;
    return `https://api.fitbit.com/${this.apiVersion}${userSubPath}${path}`;
}

Your initial proposal also removed the empty user possibility, so, I guess this would be the most comprehensive solution to handle all three use cases.

[xxzefgh]

@jmdiego hmm you are right 🤔 made a pr