SUMMARY

When a chart dimension returns an empty string; for example, using coalesce(address_line2, '') as a dimension on a Line Chart; the Results tab in the Explore view crashes with TypeError: n.includes is not a function, and the loading spinner appears frozen.

The root cause is in useTableColumns, which uses id: key || index as a fallback when the column key is empty. Since empty string is falsy in JavaScript, the expression evaluates to index; a number. This numeric ID then flows downstream into mapColumns in TableCollection/utils.tsx, where column.id?.includes('.') is called. Optional chaining (?.) only guards against null and undefined, not non-string types, so calling .includes() on a number throws a TypeError.

The fix applies two layers of defense:

At the source ([DataTableControl/index.tsx]): Coerce the fallback index to a string with String(index), ensuring column.id is always a string regardless of whether the column key is empty.

At the call site ([TableCollection/utils.tsx]: Add an explicit typeof column.id === 'string' guard before calling .includes('.'), so that even if a numeric ID somehow reaches this code path in the future, it won't crash.

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

• Before

• After

TESTING INSTRUCTIONS

1. Create a dataset with a column that can contain empty strings (e.g., address_line2)
2. Create a Line Chart (ECharts Timeseries) using coalesce(address_line2, '') as a dimension
3. Open the Results tab in the Explore view
4. Click "Create chart"; verify the Results table renders without crashing
5. Verify the chart itself renders correctly

ADDITIONAL INFORMATION

• Has associated issue:
• Required feature flags:
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API