JSON tree

First of all, thank you for this project.

Deparcer function has been developed in a good way. As far as I know, there is no documentation for the JSON parsed tree produced by parse function. How could you write a deparse function for the JSON tree without documentation? Or is there a documented version of the JSON parsed tree?
https://github.com/zhm/pg-query-parser/blob/master/dist/deparser.js