nodejs readline's cursor behavior and position - node.js

Question

I have the following code
const readline = require('readline');
const {stdin, stderr} = process;
const rl = readline.createInterface({
output: stderr,
input: stdin
})
console.log(rl.getCursorPos());
let i = 5;
while (i > 0) {
console.log('fill up with logs');
i--
}
console.log(rl.getCursorPos())
and its output
{ cols: 2, rows: 0 }
fill up with logs
fill up with logs
fill up with logs
fill up with logs
{ cols: 2, rows: 0 }
as from above the last 'getCursorPos()' should return a new position since the stderr output has been filled up with logs, instead, it returns its default value, did I misunderstand the way it works?
or is there anyway I can get cursor position and save it multiple times using readline? I've looked through using asni escape, but it seems like it can only store one cursor position at a time.

Answer 1

The position returned by readline is relative to the current cursor location, not absolute on the screen.
I was able to create a promise to get this information using the answer below containing the escape sequence for requesting terminal cursor position:
How can I get position of cursor in terminal?
const getCursorPos = () => new Promise((resolve) => {
const termcodes = { cursorGetPosition: '\u001b[6n' };
process.stdin.setEncoding('utf8');
process.stdin.setRawMode(true);
const readfx = function () {
const buf = process.stdin.read();
const str = JSON.stringify(buf); // "\u001b[9;1R"
const regex = /\[(.*)/g;
const xy = regex.exec(str)[0].replace(/\[|R"/g, '').split(';');
const pos = { rows: xy[0], cols: xy[1] };
process.stdin.setRawMode(false);
resolve(pos);
}
process.stdin.once('readable', readfx);
process.stdout.write(termcodes.cursorGetPosition);
})
const AppMain = async function () {
process.stdout.write('HELLO');
const pos = await getCursorPos();
process.stdout.write("\n");
console.log({ pos });
}
AppMain();