Table copy/download actions silently fail in fullscreen mode (closest('[data-streamdown="table-wrapper"]') breaks across the portal)

[ndozhh]

Summary

In a table's fullscreen view, the copy and download buttons do nothing. The same buttons work correctly on the inline table.

Root cause

TableCopyDropdown, TableDownloadDropdown and TableDownloadButton locate the table with:

el.closest('[data-streamdown="table-wrapper"]')?.querySelector('table')

The fullscreen overlay is rendered with createPortal(..., document.body) and its container is marked data-streamdown="table-fullscreen" (not table-wrapper). Because a portal detaches DOM ancestry, from inside the fullscreen overlay el.closest('[data-streamdown="table-wrapper"]') returns null, so every action hits the "Table not found" branch and silently no-ops.

This affects all three .closest('[data-streamdown="table-wrapper"]') call sites (copy dropdown, download dropdown, download button).

Version

• streamdown@2.5.0 (latest).
• Present since 2.4.0, when fullscreen tables were added (Full Screen Mode for tables #389). The 2.4.0 changelog states "Copy and download controls remain available in the fullscreen view", but they are non-functional.

Reproduction

1. Render <Streamdown> with a markdown table and table controls enabled (copy/download/fullscreen).
2. Click the expand/fullscreen button on the table.
3. In the fullscreen overlay, click Copy (any format) or Download → nothing is copied/downloaded (the onError path reports "Table not found").
4. Close fullscreen and use the same buttons on the inline table → they work.

Suggested fix

Broaden the lookup to also match the fullscreen container:

el.closest('[data-streamdown="table-wrapper"],[data-streamdown="table-fullscreen"]')?.querySelector('table')

Alternatively, pass the table element/ref into the fullscreen overlay instead of relying on DOM ancestry (which the portal breaks).