check for parentNode before using

[Nikhil1489]

in the getSumScroll function in the dom-helpers file

Error Traceback:

[lnagel]

@developer-ocansey — Flagging this for your review.

Recommendation: The bug still exists — apply as a quick fix to the current codebase

The bug

getSumScroll in dom-helpers.ts recursively traverses node.parentNode but doesn't guard against it being null. If a node is detached from the DOM or inside a shadow DOM, parentNode can be null, causing a crash on the next recursion.

The current code (line ~33 of dom-helpers.ts):

export function getSumScroll(node: HTMLElement): { scrollLeft: number; scrollTop: number } {
  if (node === document.body) {
    return { scrollLeft: 0, scrollTop: 0 }
  } else {
    const parent = getSumScroll(node.parentNode as HTMLElement)
    // ...
  }
}

Note that the sibling function getSumOffset already has an analogous guard (!node.offsetParent) at line ~50, so adding !node.parentNode to getSumScroll would be consistent.

Why it can't merge directly

The PR targets the old dom-helpers.js — the fix needs to be re-applied to dom-helpers.ts. It's a 1-line guard addition.

I'd suggest just applying the fix directly to dom-helpers.ts rather than trying to rebase this PR.