Firstly, thank you so much for writing this and making it public!
I have been wanting to make use of the API in a node project myself and began writing my own typescript client before finding yours, which has saved me a good chunk of time!
However, one thing I noticed though is that it does not currently provide a method for retrieving crimes in a custom defined area, which is supported by the API. I would be happy to add this myself and open a PR for it, but just wanted to make contact with you before I went ahead and did that.