Trevor

I don't think the optional chaining operator is supported in es2015.

This does the same thing that's being done here: https://github.com/infinitered/apisauce/blob/582186f3824c5d996c40d29fb57eb954e27c4a98/lib/apisauce.ts#L256-L257

I've got a PR ready to go whenever someone has time to look at it.