saveTable creating new file instead of appending existing

Hi, I am trying to load in a file in my sketch folder using loadTable, add some data to the file and then save it back to the same file.

However, the file is being downloaded in the browser to the default browser download folder instead of appending the data to the original file loaded in. How do I get the sketch to append the data to the existing file, in the sketch folder please?


A similar thing was mentioned here.
Basically, if you want to edit a file, use something other than p5.js.