Is there a programmatic way to know that a textbox is full?

[moficodes]

Basically I am generating a pdf programmatically. I have a number of different text boxes. I want to move to the next one once the current one is full?

Is there are way to know that the current textbox has no more lines left?

for e.g.

https://pdf-lib.js.org/#fill-form

this example shows setting the form. What if the text was too long.