Function resolveStreamCaretRange

src/patch-streaming-html.ts:206–253

(
  container: HTMLElement,
  cleanTrack: string,
)

/** Caret range at the live stream insertion point — end of text, not after closed blocks. */
export function resolveStreamCaretRange(
  container: HTMLElement,
  cleanTrack: string,
): { range: Range; fallback: Element } {
  const range = document.createRange();

  const tableStart = findTableStart(cleanTrack);
  if (tableStart !== -1) {
    const table = container.querySelector("table");
    if (table) {
      const tableEnd = firstCompleteTableEnd(cleanTrack, tableStart);
      if (tableEnd === -1 || cleanTrack.length <= tableEnd) {
        const partialRow = table.querySelector("tr[data-sh-partial]");
        const tailRoot = partialRow ?? table;
        const text = findLastTextNode(tailRoot);
        if (text) {
          collapseRangeAtTextEnd(range, text);
          return { range, fallback: tailRoot as Element };
        }
        collapseRangeAtElementStart(range, tailRoot as Element);
        return { range, fallback: tailRoot as Element };
      }
    }
  }

  const stack = getOpenTagStack(cleanTrack);
  const target =
    stack.length > 0 ? findDeepOpenElement(container, stack) : container;

  if (!target) {
    const text = findLastTextNode(container);
    if (text) {
      collapseRangeAtTextEnd(range, text);
      return { range, fallback: container };
    }
    collapseRangeAtElementStart(range, container);
    return { range, fallback: container };
  }

  const text = findLastTextNode(target);
  if (text) {
    collapseRangeAtTextEnd(range, text);
    return { range, fallback: target };
  }

  collapseRangeAtElementStart(range, target);
  return { range, fallback: target };
}

/** Remove text nodes wrongly appended at container root during earlier frames */
function removeOrphanContainerText(container: HTMLElement): void {