Printing list item with line break fails with Unsupported Number: NaN

[filecage]

Bug Report

Description of the problem

When using doc.list() to print list items, the process fails if one list item contains a line break (newline or return carriage characters both affected).

This is due to the internal flatten() of the text mixin calculates the amount of levels based on the number of list items given here:

pdfkit/lib/mixins/text.js

Lines 124 to 142 in 6338314

	var flatten = function(list) {
	let n = 1;
	for (let i = 0; i < list.length; i++) {
	const item = list[i];
	if (Array.isArray(item)) {
	level++;
	flatten(item);
	level--;
	} else {
	items.push(item);
	levels.push(level);
	if (listType !== 'bullet') {
	numbers.push(n++);
	}
	}
	}
	};
	flatten(list);

But the firstLine event is emitted per actual line, causing the event handler to access an undefined level item here:
https://github.com/foliojs/pdfkit/blob/6338314daf44f7f188e4cc6cb4d70fc2f2698fca/lib/mixins/text.js#L179-182

Which then results in diff being NaN and the consecutive variables this.x and wrapper.lineWidth as well.

From my knowledge of the library, I can't tell whether flatten() should produce the levels based on the actual lines or the firstLine event should only be emitted once per list item.

Code sample

With any PDFKit document, call

doc.list(['Foo\nBar']);

Your environment

• pdfkit version: 0.14.0
• Node version: 20.10.0
• Browser version (if applicable): -
• Operating System: macOS 14.1.2