Scroller: When itemSize is not set, scrolling to top results in component crash

[prx-lmo]

Describe the bug

When the property [itemSize] is not set in the html component, scrolling to top results in component crash. The scroller doesn't get shown anymore.
The reason for that is that these lines result in a NaN, because they divide by zero.

primeng/src/app/components/scroller/scroller.ts

Line 886 in 1b589db

const calculateCurrentIndex = (_pos: number, _size: number) => Math.floor(_pos / (_size || _pos));

primeng/src/app/components/scroller/scroller.ts

Line 756 in 1b589db

const calculateNumItemsInViewport = (_contentSize: number, _itemSize: number) => Math.ceil(_contentSize / (_itemSize || _contentSize));

primeng/src/app/components/scroller/scroller.ts

Line 724 in 1b589db

const calculateFirstInViewport = (_pos: number, _size: number) => Math.floor(_pos / (_size || _pos));

There are as far as I can tell, three possible fixes:

• simply prevent these lines from dividing by zero
• calculate the itemSize, either in the getter or a new function, by dividing item count by component length
• make itemSize required(worst option)

Environment

tested with Chrome and Firefox

Reproducer

No response

Angular version

17.3.6

PrimeNG version

17.15.0

Build / Runtime

Angular CLI App

Language

TypeScript

Node version (for AoT issues node --version)

20.11.1

Browser(s)

No response

Steps to reproduce the behavior

write a component like this

1. <p-scroller [items]="itemList" [autoSize]="true" [scrollHeight]="200px"> bla </p-scroller>
2. scroll a bit down
3. scroll to top

Expected behavior

well... component should'nt break