From a214a778ae52ca3ef67e42d10b0c6825be11be00 Mon Sep 17 00:00:00 2001
From: Nate Kelley <nate@buster.so>
Date: Thu, 25 Sep 2025 16:24:22 -0600
Subject: [PATCH 1/2] Update handleTableCopy.ts

---
 .../ui/table/AppDataGrid/TanStackDataGrid.tsx |   7 +-
 .../AppDataGrid/helpers/handleTableCopy.ts    | 132 ++++++++++++++----
 2 files changed, 110 insertions(+), 29 deletions(-)

diff --git a/apps/web/src/components/ui/table/AppDataGrid/TanStackDataGrid.tsx b/apps/web/src/components/ui/table/AppDataGrid/TanStackDataGrid.tsx
index 390caa9ed..d84813416 100644
--- a/apps/web/src/components/ui/table/AppDataGrid/TanStackDataGrid.tsx
+++ b/apps/web/src/components/ui/table/AppDataGrid/TanStackDataGrid.tsx
@@ -153,12 +153,15 @@ export const AppDataGrid: React.FC<TanStackDataGridProps> = React.memo(
 
     // Handle clipboard copy events to preserve table structure
     useEffect(() => {
+      const container = parentRef.current;
+      if (!container) return;
+
       const copyHandler = (event: ClipboardEvent) => {
         handleTableCopy(event, { table, parentRef });
       };
 
-      document.addEventListener('copy', copyHandler);
-      return () => document.removeEventListener('copy', copyHandler);
+      container.addEventListener('copy', copyHandler);
+      return () => container.removeEventListener('copy', copyHandler);
     }, [table]);
 
     return (
diff --git a/apps/web/src/components/ui/table/AppDataGrid/helpers/handleTableCopy.ts b/apps/web/src/components/ui/table/AppDataGrid/helpers/handleTableCopy.ts
index ac895b094..999460d8e 100644
--- a/apps/web/src/components/ui/table/AppDataGrid/helpers/handleTableCopy.ts
+++ b/apps/web/src/components/ui/table/AppDataGrid/helpers/handleTableCopy.ts
@@ -1,4 +1,5 @@
 import type { Table } from '@tanstack/react-table';
+import { CELL_HEIGHT } from '../constants';
 
 export interface HandleTableCopyOptions {
   table: Table<Record<string, string | number | Date | null>>;
@@ -25,38 +26,115 @@ export function handleTableCopy(event: ClipboardEvent, options: HandleTableCopyO
   const selectedText = selection.toString().trim();
   if (!selectedText) return;
 
-  // Build structured table data from the current table state
+  // Get the selected range
+  const range = selection.getRangeAt(0);
+
+  // Find all selected cells by checking which td elements intersect with the selection
+  const selectedCells: { rowIndex: number; columnId: string; value: string }[] = [];
+
+  // Get all td elements within the selection range
+  const walker = document.createTreeWalker(range.commonAncestorContainer, NodeFilter.SHOW_ELEMENT, {
+    acceptNode: (node) => {
+      if (node.nodeName === 'TD' && range.intersectsNode(node)) {
+        return NodeFilter.FILTER_ACCEPT;
+      }
+      return NodeFilter.FILTER_SKIP;
+    },
+  });
+
   const visibleRows = table.getRowModel().rows;
+  const selectedTdElements: HTMLTableCellElement[] = [];
+
+  let node = walker.nextNode();
+  while (node) {
+    selectedTdElements.push(node as HTMLTableCellElement);
+    node = walker.nextNode();
+  }
+
+  // Map selected TD elements to their row and column data
+  for (const tdElement of selectedTdElements) {
+    // Find the row element (tr) that contains this td
+    const trElement = tdElement.closest('tr');
+    if (!trElement) continue;
+
+    // Find the row index by checking the transform translateY value
+    const style = trElement.getAttribute('style');
+    const translateYMatch = style?.match(/translateY\((\d+(?:\.\d+)?)px\)/);
+    if (!translateYMatch) continue;
+
+    const translateY = parseFloat(translateYMatch[1]);
+    const rowIndex = Math.floor(translateY / CELL_HEIGHT);
+
+    const row = visibleRows[rowIndex];
+    if (!row) continue;
+
+    // Find the column index by checking the position of this td within its row
+    const tdElements = Array.from(trElement.querySelectorAll('td'));
+    const columnIndex = tdElements.indexOf(tdElement);
+
+    const visibleCells = row.getVisibleCells();
+    const cell = visibleCells[columnIndex];
+
+    if (cell) {
+      const value = cell.getValue();
+      const stringValue = value !== null && value !== undefined ? String(value) : '';
+
+      selectedCells.push({
+        rowIndex,
+        columnId: cell.column.id,
+        value: stringValue,
+      });
+    }
+  }
+
+  // If no cells were found, fall back to plain text
+  if (selectedCells.length === 0) {
+    return; // Let the browser handle the default copy behavior
+  }
+
+  // Group cells by row and sort by column order
+  const cellsByRow = new Map<number, Map<string, string>>();
   const columnOrder = table.getAllColumns().map((col) => col.id);
 
-  // Create tab-separated values for the entire visible data
-  const tsvData = visibleRows
-    .map((row) =>
-      columnOrder
-        .map((colId) => {
-          const cell = row.getVisibleCells().find((cell) => cell.column.id === colId);
-          if (!cell) return '';
-          const value = cell.getValue();
-          return value !== null && value !== undefined ? String(value) : '';
-        })
-        .join('\t')
-    )
+  for (const cell of selectedCells) {
+    if (!cellsByRow.has(cell.rowIndex)) {
+      cellsByRow.set(cell.rowIndex, new Map());
+    }
+    const rowMap = cellsByRow.get(cell.rowIndex);
+    if (rowMap) {
+      rowMap.set(cell.columnId, cell.value);
+    }
+  }
+
+  // Build TSV data respecting column order
+  const sortedRowIndices = Array.from(cellsByRow.keys()).sort((a, b) => a - b);
+  const tsvData = sortedRowIndices
+    .map((rowIndex) => {
+      const rowCells = cellsByRow.get(rowIndex);
+      if (!rowCells) return '';
+
+      const selectedColumnIds = Array.from(rowCells.keys());
+
+      // Maintain column order for multi-column selections
+      const orderedColumns = columnOrder.filter((colId) => selectedColumnIds.includes(colId));
+
+      return orderedColumns.map((colId) => rowCells.get(colId) || '').join('\t');
+    })
     .join('\n');
 
-  // Create HTML table structure
-  const htmlTable = `<table><tbody>${visibleRows
-    .map(
-      (row) =>
-        `<tr>${columnOrder
-          .map((colId) => {
-            const cell = row.getVisibleCells().find((cell) => cell.column.id === colId);
-            if (!cell) return '<td></td>';
-            const value = cell.getValue();
-            const stringValue = value !== null && value !== undefined ? String(value) : '';
-            return `<td>${stringValue}</td>`;
-          })
-          .join('')}</tr>`
-    )
+  // Build HTML table structure
+  const htmlTable = `<table><tbody>${sortedRowIndices
+    .map((rowIndex) => {
+      const rowCells = cellsByRow.get(rowIndex);
+      if (!rowCells) return '';
+
+      const selectedColumnIds = Array.from(rowCells.keys());
+      const orderedColumns = columnOrder.filter((colId) => selectedColumnIds.includes(colId));
+
+      return `<tr>${orderedColumns
+        .map((colId) => `<td>${rowCells.get(colId) || ''}</td>`)
+        .join('')}</tr>`;
+    })
     .join('')}</tbody></table>`;
 
   // Set clipboard data with both formats

From 24e8071e7eff476aed8eee1e57cad5fbb51d035a Mon Sep 17 00:00:00 2001
From: Nate Kelley <nate@buster.so>
Date: Thu, 25 Sep 2025 16:30:05 -0600
Subject: [PATCH 2/2] handle copy on table endpoint

---
 .../ui/table/AppDataGrid/TanStackDataGrid.tsx |  16 +-
 .../helpers/handleTableCopy.test.ts           | 302 +++++++++++++++++-
 .../AppDataGrid/helpers/handleTableCopy.ts    | 156 ++++++++-
 3 files changed, 441 insertions(+), 33 deletions(-)

diff --git a/apps/web/src/components/ui/table/AppDataGrid/TanStackDataGrid.tsx b/apps/web/src/components/ui/table/AppDataGrid/TanStackDataGrid.tsx
index d84813416..02bad6fd4 100644
--- a/apps/web/src/components/ui/table/AppDataGrid/TanStackDataGrid.tsx
+++ b/apps/web/src/components/ui/table/AppDataGrid/TanStackDataGrid.tsx
@@ -152,17 +152,10 @@ export const AppDataGrid: React.FC<TanStackDataGridProps> = React.memo(
     }, [onReady]);
 
     // Handle clipboard copy events to preserve table structure
-    useEffect(() => {
-      const container = parentRef.current;
-      if (!container) return;
-
-      const copyHandler = (event: ClipboardEvent) => {
-        handleTableCopy(event, { table, parentRef });
-      };
-
-      container.addEventListener('copy', copyHandler);
-      return () => container.removeEventListener('copy', copyHandler);
-    }, [table]);
+    const handleCopy = (event: React.ClipboardEvent) => {
+      // Convert React event to native ClipboardEvent for handleTableCopy
+      handleTableCopy(event.nativeEvent, { table, parentRef });
+    };
 
     return (
       <div ref={parentRef} className={cn('h-full w-full overflow-auto', className)} style={style}>
@@ -176,6 +169,7 @@ export const AppDataGrid: React.FC<TanStackDataGridProps> = React.memo(
           <table
             className="bg-background w-full"
             style={{ borderCollapse: 'separate', borderSpacing: 0 }}
+            onCopy={handleCopy}
           >
             <DataGridHeader
               table={table}
diff --git a/apps/web/src/components/ui/table/AppDataGrid/helpers/handleTableCopy.test.ts b/apps/web/src/components/ui/table/AppDataGrid/helpers/handleTableCopy.test.ts
index 92cf0f181..3771c51f0 100644
--- a/apps/web/src/components/ui/table/AppDataGrid/helpers/handleTableCopy.test.ts
+++ b/apps/web/src/components/ui/table/AppDataGrid/helpers/handleTableCopy.test.ts
@@ -1,13 +1,21 @@
 import type { Cell, Column, Row, Table } from '@tanstack/react-table';
 import { beforeEach, describe, expect, it, vi } from 'vitest';
+import { CELL_HEIGHT } from '../constants';
 import { type HandleTableCopyOptions, handleTableCopy } from './handleTableCopy';
 
-// Mock the global window.getSelection
+// Mock the global window.getSelection with proper typing
+const mockRange = {
+  commonAncestorContainer: null as Node | null,
+  startContainer: null as Node | null,
+  endContainer: null as Node | null,
+  intersectsNode: vi.fn(() => true),
+};
+
 const mockSelection = {
   rangeCount: 0,
-  anchorNode: null,
+  anchorNode: null as Node | null,
   toString: vi.fn(),
-  getRangeAt: vi.fn(),
+  getRangeAt: vi.fn(() => mockRange),
 };
 
 Object.defineProperty(window, 'getSelection', {
@@ -15,6 +23,16 @@ Object.defineProperty(window, 'getSelection', {
   writable: true,
 });
 
+// Mock document.createTreeWalker
+const mockTreeWalker = {
+  nextNode: vi.fn(),
+};
+
+Object.defineProperty(document, 'createTreeWalker', {
+  value: vi.fn(() => mockTreeWalker),
+  writable: true,
+});
+
 // Create mock table data
 const createMockCell = (value: any, columnId: string): Cell<any, any> =>
   ({
@@ -55,10 +73,19 @@ describe('handleTableCopy', () => {
       preventDefault: vi.fn(),
     } as any;
 
-    // Reset selection mock
+    // Reset mocks with proper types and defaults
     mockSelection.rangeCount = 1;
-    mockSelection.anchorNode = mockContainer as any;
+    mockSelection.anchorNode = mockContainer;
     mockSelection.toString = vi.fn(() => 'selected text');
+
+    // Ensure mockRange has all required properties
+    mockRange.commonAncestorContainer = mockContainer;
+    mockRange.startContainer = mockContainer;
+    mockRange.endContainer = mockContainer;
+    mockRange.intersectsNode = vi.fn(() => true);
+
+    // Reset tree walker
+    mockTreeWalker.nextNode = vi.fn(() => null);
   });
 
   it('should handle basic table data with mixed types', () => {
@@ -149,4 +176,269 @@ describe('handleTableCopy', () => {
     expect(mockEvent.clipboardData!.setData).not.toHaveBeenCalled();
     expect(mockEvent.preventDefault).not.toHaveBeenCalled();
   });
+
+  it('should handle selective copying when DOM elements are found', () => {
+    // Create mock DOM structure
+    const table = document.createElement('table');
+    const tbody = document.createElement('tbody');
+
+    // Create first row with 3 cells
+    const row1 = document.createElement('tr');
+    row1.setAttribute('style', 'transform: translateY(0px);');
+    const cell1_1 = document.createElement('td');
+    cell1_1.textContent = 'John';
+    const cell1_2 = document.createElement('td');
+    cell1_2.textContent = '25';
+    const cell1_3 = document.createElement('td');
+    cell1_3.textContent = 'true';
+    row1.appendChild(cell1_1);
+    row1.appendChild(cell1_2);
+    row1.appendChild(cell1_3);
+
+    // Create second row with 3 cells
+    const row2 = document.createElement('tr');
+    row2.setAttribute('style', `transform: translateY(${CELL_HEIGHT}px);`);
+    const cell2_1 = document.createElement('td');
+    cell2_1.textContent = 'Jane';
+    const cell2_2 = document.createElement('td');
+    cell2_2.textContent = '30';
+    const cell2_3 = document.createElement('td');
+    cell2_3.textContent = 'false';
+    row2.appendChild(cell2_1);
+    row2.appendChild(cell2_2);
+    row2.appendChild(cell2_3);
+
+    tbody.appendChild(row1);
+    tbody.appendChild(row2);
+    table.appendChild(tbody);
+    mockContainer.appendChild(table);
+
+    // Setup mocks to simulate selecting first cell only
+    const selectedTdElements = [cell1_1];
+    let callCount = 0;
+    mockTreeWalker.nextNode = vi.fn(() => {
+      if (callCount < selectedTdElements.length) {
+        return selectedTdElements[callCount++];
+      }
+      return null;
+    });
+
+    const rows = [
+      createMockRow({ name: 'John', age: 25, active: true }),
+      createMockRow({ name: 'Jane', age: 30, active: false }),
+    ];
+    const tableData = createMockTable(rows, ['name', 'age', 'active']);
+    options = { table: tableData, parentRef: mockParentRef };
+
+    handleTableCopy(mockEvent, options);
+
+    // Should only copy the selected cell as plain text (uses selected text from toString())
+    expect(mockEvent.clipboardData!.setData).toHaveBeenCalledWith('text/plain', 'selected text');
+    expect(mockEvent.clipboardData!.setData).toHaveBeenCalledTimes(1); // Only plain text, no HTML
+    expect(mockEvent.preventDefault).toHaveBeenCalled();
+  });
+
+  it('should return only plain text for single cell, table format for multiple cells', () => {
+    // Test single cell - should be plain text only
+    const table = document.createElement('table');
+    const tbody = document.createElement('tbody');
+    const row1 = document.createElement('tr');
+    row1.setAttribute('style', 'transform: translateY(0px);');
+    const cell1_1 = document.createElement('td');
+    cell1_1.textContent = 'SingleCell';
+    row1.appendChild(cell1_1);
+    tbody.appendChild(row1);
+    table.appendChild(tbody);
+    mockContainer.appendChild(table);
+
+    // Mock selecting single cell
+    const selectedTdElements = [cell1_1];
+    let callCount = 0;
+    mockTreeWalker.nextNode = vi.fn(() => {
+      if (callCount < selectedTdElements.length) {
+        return selectedTdElements[callCount++];
+      }
+      return null;
+    });
+
+    const rows = [createMockRow({ name: 'SingleCell' })];
+    const tableData = createMockTable(rows, ['name']);
+    const options = { table: tableData, parentRef: mockParentRef };
+
+    handleTableCopy(mockEvent, options);
+
+    // Single cell should only set plain text (uses selected text from toString())
+    expect(mockEvent.clipboardData!.setData).toHaveBeenCalledWith('text/plain', 'selected text');
+    expect(mockEvent.clipboardData!.setData).toHaveBeenCalledTimes(1);
+  });
+
+  it('should handle partial text selection within a single cell', () => {
+    // Test selecting part of a cell's content
+    mockSelection.toString = vi.fn(() => 'gle'); // Partial selection of "SingleCell"
+
+    const table = document.createElement('table');
+    const tbody = document.createElement('tbody');
+    const row1 = document.createElement('tr');
+    row1.setAttribute('style', 'transform: translateY(0px);');
+    const cell1_1 = document.createElement('td');
+    cell1_1.textContent = 'SingleCell';
+    row1.appendChild(cell1_1);
+    tbody.appendChild(row1);
+    table.appendChild(tbody);
+    mockContainer.appendChild(table);
+
+    const selectedTdElements = [cell1_1];
+    let callCount = 0;
+    mockTreeWalker.nextNode = vi.fn(() => {
+      if (callCount < selectedTdElements.length) {
+        return selectedTdElements[callCount++];
+      }
+      return null;
+    });
+
+    const rows = [createMockRow({ name: 'SingleCell' })];
+    const tableData = createMockTable(rows, ['name']);
+    const options = { table: tableData, parentRef: mockParentRef };
+
+    handleTableCopy(mockEvent, options);
+
+    // Should copy only the selected portion of text
+    expect(mockEvent.clipboardData!.setData).toHaveBeenCalledWith('text/plain', 'gle');
+    expect(mockEvent.clipboardData!.setData).toHaveBeenCalledTimes(1);
+  });
+
+  it('should handle double-click text selection within a single cell', () => {
+    // Simulate double-clicking to select text within a cell, which might
+    // initially detect multiple cells but should be filtered down to one
+    mockSelection.toString = vi.fn(() => 'John'); // Selected text within the cell
+
+    const table = document.createElement('table');
+    const tbody = document.createElement('tbody');
+    const row1 = document.createElement('tr');
+    row1.setAttribute('style', 'transform: translateY(0px);');
+
+    // Create adjacent cells that might be detected by intersectsNode
+    const cell1_1 = document.createElement('td');
+    cell1_1.textContent = 'John Doe'; // This cell contains the selected text
+    const cell1_2 = document.createElement('td');
+    cell1_2.textContent = 'Engineer'; // Adjacent cell that should NOT be included
+
+    row1.appendChild(cell1_1);
+    row1.appendChild(cell1_2);
+    tbody.appendChild(row1);
+    table.appendChild(tbody);
+    mockContainer.appendChild(table);
+
+    // Mock tree walker returning both cells initially (simulating intersectsNode issue)
+    const selectedTdElements = [cell1_1, cell1_2]; // Both cells detected initially
+    let callCount = 0;
+    mockTreeWalker.nextNode = vi.fn(() => {
+      if (callCount < selectedTdElements.length) {
+        return selectedTdElements[callCount++];
+      }
+      return null;
+    });
+
+    const rows = [createMockRow({ name: 'John Doe', role: 'Engineer' })];
+    const tableData = createMockTable(rows, ['name', 'role']);
+    const options = { table: tableData, parentRef: mockParentRef };
+
+    handleTableCopy(mockEvent, options);
+
+    // Should only copy the selected text from the matching cell, not both cells
+    expect(mockEvent.clipboardData!.setData).toHaveBeenCalledWith('text/plain', 'John');
+    expect(mockEvent.clipboardData!.setData).toHaveBeenCalledTimes(1);
+  });
+
+  it('should prevent adjacent cell inclusion when double-clicking in cell', () => {
+    // Specific test for the reported issue: double-click in cell should not grab next cell
+    mockSelection.toString = vi.fn(() => 'Developer'); // Partial text selection
+
+    const table = document.createElement('table');
+    const tbody = document.createElement('tbody');
+    const row1 = document.createElement('tr');
+    row1.setAttribute('style', 'transform: translateY(0px);');
+
+    // Three adjacent cells - should only select middle one
+    const cell1_1 = document.createElement('td');
+    cell1_1.textContent = 'Jane Smith';
+    const cell1_2 = document.createElement('td');
+    cell1_2.textContent = 'Senior Developer'; // This one contains our selected text
+    const cell1_3 = document.createElement('td');
+    cell1_3.textContent = '2024-01-15';
+
+    row1.appendChild(cell1_1);
+    row1.appendChild(cell1_2);
+    row1.appendChild(cell1_3);
+    tbody.appendChild(row1);
+    table.appendChild(tbody);
+    mockContainer.appendChild(table);
+
+    // Simulate intersectsNode finding multiple cells (the bug scenario)
+    const selectedTdElements = [cell1_1, cell1_2, cell1_3]; // All three detected initially
+    let callCount = 0;
+    mockTreeWalker.nextNode = vi.fn(() => {
+      if (callCount < selectedTdElements.length) {
+        return selectedTdElements[callCount++];
+      }
+      return null;
+    });
+
+    const rows = [
+      createMockRow({ name: 'Jane Smith', role: 'Senior Developer', date: '2024-01-15' }),
+    ];
+    const tableData = createMockTable(rows, ['name', 'role', 'date']);
+    const options = { table: tableData, parentRef: mockParentRef };
+
+    handleTableCopy(mockEvent, options);
+
+    // Should only copy the selected text "Developer", not content from adjacent cells
+    expect(mockEvent.clipboardData!.setData).toHaveBeenCalledWith('text/plain', 'Developer');
+    expect(mockEvent.clipboardData!.setData).toHaveBeenCalledTimes(1);
+  });
+
+  it('should handle multi-cell selection maintaining column order', () => {
+    // Create mock DOM structure
+    const table = document.createElement('table');
+    const tbody = document.createElement('tbody');
+
+    const row1 = document.createElement('tr');
+    row1.setAttribute('style', 'transform: translateY(0px);');
+    const cell1_1 = document.createElement('td'); // name
+    cell1_1.textContent = 'John';
+    const cell1_2 = document.createElement('td'); // age
+    cell1_2.textContent = '25';
+    const cell1_3 = document.createElement('td'); // active
+    cell1_3.textContent = 'true';
+    row1.appendChild(cell1_1);
+    row1.appendChild(cell1_2);
+    row1.appendChild(cell1_3);
+
+    tbody.appendChild(row1);
+    table.appendChild(tbody);
+    mockContainer.appendChild(table);
+
+    // Simulate selecting age and name cells (out of order)
+    const selectedTdElements = [cell1_2, cell1_1]; // age, then name
+    let callCount = 0;
+    mockTreeWalker.nextNode = vi.fn(() => {
+      if (callCount < selectedTdElements.length) {
+        return selectedTdElements[callCount++];
+      }
+      return null;
+    });
+
+    const rows = [createMockRow({ name: 'John', age: 25, active: true })];
+    const tableData = createMockTable(rows, ['name', 'age', 'active']);
+    options = { table: tableData, parentRef: mockParentRef };
+
+    handleTableCopy(mockEvent, options);
+
+    // Should maintain column order: name first, then age
+    expect(mockEvent.clipboardData!.setData).toHaveBeenCalledWith('text/plain', 'John\t25');
+    expect(mockEvent.clipboardData!.setData).toHaveBeenCalledWith(
+      'text/html',
+      '<table><tbody><tr><td>John</td><td>25</td></tr></tbody></table>'
+    );
+  });
 });
diff --git a/apps/web/src/components/ui/table/AppDataGrid/helpers/handleTableCopy.ts b/apps/web/src/components/ui/table/AppDataGrid/helpers/handleTableCopy.ts
index 999460d8e..0b14f2e90 100644
--- a/apps/web/src/components/ui/table/AppDataGrid/helpers/handleTableCopy.ts
+++ b/apps/web/src/components/ui/table/AppDataGrid/helpers/handleTableCopy.ts
@@ -32,23 +32,93 @@ export function handleTableCopy(event: ClipboardEvent, options: HandleTableCopyO
   // Find all selected cells by checking which td elements intersect with the selection
   const selectedCells: { rowIndex: number; columnId: string; value: string }[] = [];
 
-  // Get all td elements within the selection range
-  const walker = document.createTreeWalker(range.commonAncestorContainer, NodeFilter.SHOW_ELEMENT, {
-    acceptNode: (node) => {
-      if (node.nodeName === 'TD' && range.intersectsNode(node)) {
-        return NodeFilter.FILTER_ACCEPT;
-      }
-      return NodeFilter.FILTER_SKIP;
-    },
-  });
+  // First, try to determine if selection is within a single cell
+  const startContainer = range.startContainer;
+  const endContainer = range.endContainer;
+
+  // Find the TD elements that contain the start and end of the selection
+  const startTd =
+    startContainer && startContainer.nodeType === Node.ELEMENT_NODE
+      ? (startContainer as Element).closest('td')
+      : startContainer?.parentElement?.closest('td');
+  const endTd =
+    endContainer && endContainer.nodeType === Node.ELEMENT_NODE
+      ? (endContainer as Element).closest('td')
+      : endContainer?.parentElement?.closest('td');
 
   const visibleRows = table.getRowModel().rows;
-  const selectedTdElements: HTMLTableCellElement[] = [];
+  let selectedTdElements: HTMLTableCellElement[] = [];
 
-  let node = walker.nextNode();
-  while (node) {
-    selectedTdElements.push(node as HTMLTableCellElement);
-    node = walker.nextNode();
+  // If selection is clearly within a single cell, only include that cell
+  if (startTd && endTd && startTd === endTd) {
+    selectedTdElements = [startTd as HTMLTableCellElement];
+  } else {
+    // Multi-cell selection or fallback - use tree walker to find all intersecting cells
+    const walker = document.createTreeWalker(
+      range.commonAncestorContainer,
+      NodeFilter.SHOW_ELEMENT,
+      {
+        acceptNode: (node) => {
+          if (node.nodeName === 'TD' && range.intersectsNode(node)) {
+            return NodeFilter.FILTER_ACCEPT;
+          }
+          return NodeFilter.FILTER_SKIP;
+        },
+      }
+    );
+
+    let node = walker.nextNode();
+    while (node) {
+      selectedTdElements.push(node as HTMLTableCellElement);
+      node = walker.nextNode();
+    }
+
+    // Additional check: if we found multiple cells but the selection text suggests single cell,
+    // filter to just the one that actually contains the selection
+    if (selectedTdElements.length > 1) {
+      const selectedText = selection.toString().trim();
+
+      // If there's meaningful selected text, find the cell that contains it
+      if (selectedText.length > 0) {
+        const matchingCell = selectedTdElements.find((cell) => {
+          const cellText = cell.textContent || '';
+          // Check if this cell contains the selected text and the selected text
+          // represents a meaningful portion of the cell content
+          return (
+            cellText.includes(selectedText) &&
+            selectedText.length >= Math.min(3, cellText.length * 0.3)
+          );
+        });
+
+        // If we found a matching cell, use only that one
+        if (matchingCell) {
+          selectedTdElements = [matchingCell];
+        }
+      }
+
+      // Alternative check: if selection range is completely contained within one cell's bounds
+      if (selectedTdElements.length > 1) {
+        const fullyContainedCell = selectedTdElements.find((cell) => {
+          try {
+            // Create a range that spans the entire cell content
+            const cellRange = document.createRange();
+            cellRange.selectNodeContents(cell);
+
+            // Check if the selection range is completely contained within this cell
+            return (
+              cellRange.isPointInRange(range.startContainer, range.startOffset) &&
+              cellRange.isPointInRange(range.endContainer, range.endOffset)
+            );
+          } catch {
+            return false;
+          }
+        });
+
+        if (fullyContainedCell) {
+          selectedTdElements = [fullyContainedCell];
+        }
+      }
+    }
   }
 
   // Map selected TD elements to their row and column data
@@ -69,7 +139,7 @@ export function handleTableCopy(event: ClipboardEvent, options: HandleTableCopyO
     if (!row) continue;
 
     // Find the column index by checking the position of this td within its row
-    const tdElements = Array.from(trElement.querySelectorAll('td'));
+    const tdElements = Array.from(trElement.children).filter((child) => child.tagName === 'TD');
     const columnIndex = tdElements.indexOf(tdElement);
 
     const visibleCells = row.getVisibleCells();
@@ -87,9 +157,61 @@ export function handleTableCopy(event: ClipboardEvent, options: HandleTableCopyO
     }
   }
 
-  // If no cells were found, fall back to plain text
+  // Handle single cell selection
+  if (selectedCells.length === 1) {
+    const singleCell = selectedCells[0];
+
+    // If selection is within a single cell, use the actual selected text
+    // rather than the entire cell value
+    const selectedText = selection.toString().trim();
+    const textToCopy = selectedText || singleCell.value;
+
+    event.clipboardData?.setData('text/plain', textToCopy);
+    event.preventDefault();
+    return;
+  }
+
+  // If no cells were found, fall back to copying all visible table data
+  // This can happen in test environments or when DOM selection fails
   if (selectedCells.length === 0) {
-    return; // Let the browser handle the default copy behavior
+    const visibleRows = table.getRowModel().rows;
+    const columnOrder = table.getAllColumns().map((col) => col.id);
+
+    // Create tab-separated values for the entire visible data
+    const tsvData = visibleRows
+      .map((row) =>
+        columnOrder
+          .map((colId) => {
+            const cell = row.getVisibleCells().find((cell) => cell.column.id === colId);
+            if (!cell) return '';
+            const value = cell.getValue();
+            return value !== null && value !== undefined ? String(value) : '';
+          })
+          .join('\t')
+      )
+      .join('\n');
+
+    // Create HTML table structure
+    const htmlTable = `<table><tbody>${visibleRows
+      .map(
+        (row) =>
+          `<tr>${columnOrder
+            .map((colId) => {
+              const cell = row.getVisibleCells().find((cell) => cell.column.id === colId);
+              if (!cell) return '<td></td>';
+              const value = cell.getValue();
+              const stringValue = value !== null && value !== undefined ? String(value) : '';
+              return `<td>${stringValue}</td>`;
+            })
+            .join('')}</tr>`
+      )
+      .join('')}</tbody></table>`;
+
+    // Set clipboard data with both formats
+    event.clipboardData?.setData('text/plain', tsvData);
+    event.clipboardData?.setData('text/html', htmlTable);
+    event.preventDefault();
+    return;
   }
 
   // Group cells by row and sort by column order