From d4f9bfd640176d88eb336914d45d7d6355632b3a Mon Sep 17 00:00:00 2001
From: sadmann7 <sadmann898@gmail.com>
Date: Sun, 14 Jun 2026 16:52:16 +0600
Subject: [PATCH] fix(data-grid): fix range pasting

---
 src/hooks/use-data-grid.ts | 64 +++++++++++++++++++++++++++++++++-----
 src/lib/data-grid.ts       |  2 +-
 2 files changed, 57 insertions(+), 9 deletions(-)

diff --git a/src/hooks/use-data-grid.ts b/src/hooks/use-data-grid.ts
index a489bc74c..288e95295 100644
--- a/src/hooks/use-data-grid.ts
+++ b/src/hooks/use-data-grid.ts
@@ -404,11 +404,21 @@ function useDataGrid<TData>({
         }
       }
 
-      const newData: TData[] = new Array(currentData.length);
-
-      for (let i = 0; i < currentData.length; i++) {
+      // Determine the full range of indices to cover — including any rows
+      // that were just added by onRowsAdd and are in the table but may not
+      // yet be reflected in propsRef.current.data (stale closure timing).
+      const maxUpdateIndex =
+        rowUpdatesMap.size > 0
+          ? Math.max(...Array.from(rowUpdatesMap.keys()))
+          : -1;
+      const dataLength = Math.max(currentData.length, maxUpdateIndex + 1);
+
+      const newData: TData[] = new Array(dataLength);
+
+      for (let i = 0; i < dataLength; i++) {
         const updates = rowUpdatesMap.get(i);
-        const existingRow = currentData[i];
+        // Fall back to the table's row data for rows not yet in currentData
+        const existingRow = currentData[i] ?? rows?.[i]?.original;
 
         if (existingRow == null) continue;
 
@@ -718,13 +728,51 @@ function useDataGrid<TData>({
           if (!clipboardText) return;
         }
 
-        const pastedData = parseTsv(clipboardText, navigableColumnIds.length);
+        const rawPastedData = parseTsv(
+          clipboardText,
+          navigableColumnIds.length,
+        );
+
+        // When clipboard has exactly one cell and the user has multiple cells
+        // selected, fill the entire selection with that single value.
+        const selectionCells = currentState.selectionState.selectedCells;
+        const isSingleCellClipboard =
+          rawPastedData.length === 1 && (rawPastedData[0]?.length ?? 0) === 1;
 
-        const startRowIndex = currentState.focusedCell.rowIndex;
-        const startColIndex = navigableColumnIds.indexOf(
+        let pastedData = rawPastedData;
+        let startRowIndex = currentState.focusedCell.rowIndex;
+        let startColIndex = navigableColumnIds.indexOf(
           currentState.focusedCell.columnId,
         );
 
+        if (isSingleCellClipboard && selectionCells.size > 1) {
+          const singleValue = rawPastedData[0]?.[0] ?? "";
+          let minRow = Infinity;
+          let maxRow = -Infinity;
+          let minColIdx = Infinity;
+          let maxColIdx = -Infinity;
+
+          for (const cellKey of selectionCells) {
+            const { rowIndex, columnId } = parseCellKey(cellKey);
+            const colIdx = navigableColumnIds.indexOf(columnId);
+            if (colIdx === -1) continue;
+            minRow = Math.min(minRow, rowIndex);
+            maxRow = Math.max(maxRow, rowIndex);
+            minColIdx = Math.min(minColIdx, colIdx);
+            maxColIdx = Math.max(maxColIdx, colIdx);
+          }
+
+          if (minRow !== Infinity) {
+            startRowIndex = minRow;
+            startColIndex = minColIdx;
+            const numRows = maxRow - minRow + 1;
+            const numCols = maxColIdx - minColIdx + 1;
+            pastedData = Array.from({ length: numRows }, () =>
+              Array.from({ length: numCols }, () => singleValue),
+            );
+          }
+        }
+
         if (startColIndex === -1) return;
 
         const rowCount = rows.length ?? propsRef.current.data.length;
@@ -855,7 +903,7 @@ function useDataGrid<TData>({
               case "select": {
                 const options = cellOpts?.options ?? [];
                 if (!pastedValue) {
-                  processedValue = "";
+                  processedValue = null;
                 } else {
                   const matched = matchSelectOption(pastedValue, options);
                   if (matched) processedValue = matched;
diff --git a/src/lib/data-grid.ts b/src/lib/data-grid.ts
index 1c83aff14..0a84142e2 100644
--- a/src/lib/data-grid.ts
+++ b/src/lib/data-grid.ts
@@ -327,7 +327,7 @@ export function parseTsv(
     return rows;
   }
 
-  const lines = text.split("\n");
+  const lines = text.split("\n").map((l) => l.replace(/\r$/, ""));
   let maxTabCount = 0;
   for (const line of lines) {
     const n = countTabs(line);