Editing CSV file with Bangle.js v2

I'm working on a project that involves data logging in a CSV, but where there should be the option of editing/deleting the last line of the CSV. I'm not sure how to go about this with a Bangle.

I was thinking maybe something like loading the whole file into a string, deleting the last line, then re-saving it. But I'm worried about the size of the string being larger than the watch can handle if the file gets very long.

var file = require("Storage").open("positions.csv",­"r");

// Read whole file with very long length parameter
csv = file.read(100000);

// Convert to array of lines
csvNew = csv.split('\n');

// Remove last line
csvNew.pop();

// Join back into single string
csvNew = csvNew.join("\n");

var file = require("Storage").open("positions.csv",­ "w");

file.write(csvNew);

Is there a better way to do this?

Edit: Oh, maybe I can somehow access just the last chunk with the file\5 notation? I don't know if that's a thing.

It doesn't necessarily have to be in CSV format.