Add csv.showTrailingEmptyRow setting to optionally hide trailing empty row

Author: jonaraphael

README.md

@@ -101,6 +101,7 @@ Global (Settings UI or `settings.json`):
 - `csv.columnColorMode` (string, default `type`): `type` keeps CSV’s type-based column colors; `theme` uses your theme foreground color for all columns.
 - `csv.columnColorPalette` (string, default `default`): Type-color palette when `csv.columnColorMode` is `type`. `cool` biases colors toward greens/blues; `warm` biases colors toward oranges/reds.
 - `csv.clickableLinks` (boolean, default `true`): Make URLs in cells clickable. Ctrl/Cmd+click to open links.
+- `csv.showTrailingEmptyRow` (boolean, default `true`): Show the extra empty row at the end of the table. Turn this off to hide that visual append row.
 - `csv.separatorMode` (string, default `extension`): Separator selection mode when no per-file override exists. `extension` uses extension mapping, `auto` detects from content first, `default` always uses `csv.defaultSeparator`.
 - `csv.defaultSeparator` (string, default `,`): Fallback separator. Use `\\t` in `settings.json` for tabs.
 - `csv.separatorByExtension` (object): Extension-to-separator mapping (defaults include `.csv`→`,`, `.tsv`/`.tab`→tab, `.psv`→`|`).

package.json

@@ -145,6 +145,11 @@
           "default": true,
           "description": "Make URLs in cells clickable. Ctrl/Cmd+click to open links."
         },
+        "csv.showTrailingEmptyRow": {
+          "type": "boolean",
+          "default": true,
+          "description": "Show an extra empty row at the end of the table for quick append-style editing."
+        },
         "csv.separatorMode": {
           "type": "string",
           "enum": [

src/CsvEditorProvider.ts

@@ -976,6 +976,7 @@ class CsvEditorController {
     const clickableLinks = config.get<boolean>('clickableLinks', true);
     const columnColorMode = config.get<string>('columnColorMode', 'type');
     const columnColorPalette = config.get<string>('columnColorPalette', 'default');
+    const showTrailingEmptyRow = config.get<boolean>('showTrailingEmptyRow', true);
 
     const { tableHtml, chunksJson, colorCss } =
       this.generateTableAndChunks(
@@ -985,7 +986,8 @@ class CsvEditorController {
         hiddenRows,
         clickableLinks,
         columnColorMode,
-        columnColorPalette
+        columnColorPalette,
+        showTrailingEmptyRow
       );
 
     const nonce = this.getNonce();
@@ -1009,7 +1011,8 @@ class CsvEditorController {
     hiddenRows: number,
     clickableLinks: boolean,
     columnColorMode: string,
-    columnColorPalette: string
+    columnColorPalette: string,
+    showTrailingEmptyRow: boolean
   ): { tableHtml: string; chunksJson: string; colorCss: string } {
     let headerFlag = treatHeader;
     const totalRows = data.length;
@@ -1045,7 +1048,11 @@ class CsvEditorController {
     const CHUNK_SIZE = 1000;
     const allRows = headerFlag ? bodyData : data.slice(offset);
     const allRowsCount = allRows.length; // preserve total before any truncation
-    const serialIndexWidthCh = Math.max(4, String(Math.max(1, allRowsCount + 1)).length + 1);
+    // Always keep one editable row for fully empty views; otherwise allow disabling the
+    // trailing virtual row via settings.
+    const includeTrailingEmptyRow = showTrailingEmptyRow || allRowsCount === 0;
+    const serialIndexMaxDisplay = includeTrailingEmptyRow ? allRowsCount + 1 : allRowsCount;
+    const serialIndexWidthCh = Math.max(4, String(Math.max(1, serialIndexMaxDisplay)).length + 1);
     const chunks: string[] = [];
     const chunked = allRowsCount > CHUNK_SIZE;
 
@@ -1113,7 +1120,7 @@ class CsvEditorController {
         }
         tableHtml += `</tr>`;
       });
-      if (!chunked) {
+      if (!chunked && includeTrailingEmptyRow) {
         const virtualAbs = offset + 1 + bodyData.length;
         const idxCell = addSerialIndex ? `<td tabindex="0" style="min-width: ${serialIndexWidthCh}ch; max-width: ${serialIndexWidthCh}ch; border: 1px solid ${isDark ? '#555' : '#ccc'}; color: #888;" data-row="${virtualAbs}" data-col="-1">${bodyData.length + 1}</td>` : '';
         const dataCells = Array.from({ length: numColumns }, (_, i) => `<td tabindex="0" style="min-width: ${Math.min(columnWidths[i] || 0, 100)}ch; max-width: 100ch; border: 1px solid ${isDark ? '#555' : '#ccc'}; color: ${columnColors[i]}; overflow: visible; white-space: pre-wrap; overflow-wrap: anywhere;" data-row="${virtualAbs}" data-col="${i}"></td>`).join('');
@@ -1138,7 +1145,7 @@ class CsvEditorController {
         }
         tableHtml += `</tr>`;
       });
-      if (!chunked) {
+      if (!chunked && includeTrailingEmptyRow) {
         const virtualAbs = offset + nonHeaderRows.length;
         const displayIdx = nonHeaderRows.length + 1;
         const idxCell = addSerialIndex ? `<td tabindex="0" style="min-width: ${serialIndexWidthCh}ch; max-width: ${serialIndexWidthCh}ch; border: 1px solid ${isDark ? '#555' : '#ccc'}; color: #888;" data-row="${virtualAbs}" data-col="-1">${displayIdx}</td>` : '';
@@ -1148,8 +1155,8 @@ class CsvEditorController {
       tableHtml += `</tbody>`;
     }
     tableHtml += `</table>`;
-    // If chunked, append a final chunk with the virtual row so it appears at the end
-    if (chunked) {
+    // If chunked, append a final chunk with the virtual row so it appears at the end.
+    if (chunked && includeTrailingEmptyRow) {
       const startAbs = headerFlag ? offset + 1 : offset;
       const virtualAbs = startAbs + allRowsCount;
       const displayIdx = allRowsCount + 1;
@@ -2292,10 +2299,20 @@ export class CsvEditorProvider implements vscode.CustomTextEditorProvider {
       hiddenRows: number,
       clickableLinks: boolean = true,
       columnColorMode: 'type' | 'theme' = 'type',
-      columnColorPalette: 'default' | 'cool' | 'warm' = 'default'
+      columnColorPalette: 'default' | 'cool' | 'warm' = 'default',
+      showTrailingEmptyRow: boolean = true
     ): { chunkCount: number; hasTable: boolean } {
       const c: any = new (CsvEditorController as any)({} as any);
-      const result = c.generateTableAndChunks(data, treatHeader, addSerialIndex, hiddenRows, clickableLinks, columnColorMode, columnColorPalette);
+      const result = c.generateTableAndChunks(
+        data,
+        treatHeader,
+        addSerialIndex,
+        hiddenRows,
+        clickableLinks,
+        columnColorMode,
+        columnColorPalette,
+        showTrailingEmptyRow
+      );
       try {
         const chunks = JSON.parse(result.chunksJson);
         return { chunkCount: Array.isArray(chunks) ? chunks.length : 0, hasTable: typeof result.tableHtml === 'string' && result.tableHtml.includes('<table') };
@@ -2310,10 +2327,20 @@ export class CsvEditorProvider implements vscode.CustomTextEditorProvider {
       hiddenRows: number,
       clickableLinks: boolean = true,
       columnColorMode: 'type' | 'theme' = 'type',
-      columnColorPalette: 'default' | 'cool' | 'warm' = 'default'
+      columnColorPalette: 'default' | 'cool' | 'warm' = 'default',
+      showTrailingEmptyRow: boolean = true
     ): { tableHtml: string; chunks: string[] } {
       const c: any = new (CsvEditorController as any)({} as any);
-      const result = c.generateTableAndChunks(data, treatHeader, addSerialIndex, hiddenRows, clickableLinks, columnColorMode, columnColorPalette);
+      const result = c.generateTableAndChunks(
+        data,
+        treatHeader,
+        addSerialIndex,
+        hiddenRows,
+        clickableLinks,
+        columnColorMode,
+        columnColorPalette,
+        showTrailingEmptyRow
+      );
       let chunks: string[] = [];
       try { chunks = JSON.parse(result.chunksJson); } catch {}
       return { tableHtml: result.tableHtml, chunks };

src/test/virtuals-invariants.test.ts

@@ -53,6 +53,61 @@ describe('Virtual row and cell invariants', () => {
     }
   });
 
+  it('can hide the trailing virtual row for non-empty non-chunked data', () => {
+    const data = [
+      ['a'],
+      ['b', 'c', 'd']
+    ];
+    const { tableHtml, chunks } = CsvEditorProvider.__test.generateTableAndChunksRaw(
+      data,
+      /*treatHeader*/ false,
+      /*addSerialIndex*/ false,
+      /*hiddenRows*/ 0,
+      /*clickableLinks*/ true,
+      /*columnColorMode*/ 'type',
+      /*columnColorPalette*/ 'default',
+      /*showTrailingEmptyRow*/ false
+    );
+    assert.strictEqual(chunks.length, 0);
+    assert.ok(!tableHtml.includes('data-row="2" data-col="0"'));
+    assert.ok(!tableHtml.includes('data-row="2" data-col="1"'));
+    assert.ok(!tableHtml.includes('data-row="2" data-col="2"'));
+  });
+
+  it('can hide the trailing virtual row for non-empty chunked data', () => {
+    const rows: string[][] = Array.from({ length: 1500 }, (_, i) => [String(i + 1), 'x', 'y']);
+    const { tableHtml, chunks } = CsvEditorProvider.__test.generateTableAndChunksRaw(
+      rows,
+      /*treatHeader*/ false,
+      /*addSerialIndex*/ false,
+      /*hiddenRows*/ 0,
+      /*clickableLinks*/ true,
+      /*columnColorMode*/ 'type',
+      /*columnColorPalette*/ 'default',
+      /*showTrailingEmptyRow*/ false
+    );
+    assert.ok(!tableHtml.includes('data-row="1500"'));
+    // Only one chunk should remain (rows 1000-1499). No final virtual-row chunk.
+    assert.strictEqual(chunks.length, 1);
+    assert.ok(!chunks[0].includes('data-row="1500"'));
+  });
+
+  it('still renders one editable row for empty data even when trailing row is disabled', () => {
+    const rows: string[][] = [];
+    const { tableHtml, chunks } = CsvEditorProvider.__test.generateTableAndChunksRaw(
+      rows,
+      /*treatHeader*/ false,
+      /*addSerialIndex*/ false,
+      /*hiddenRows*/ 0,
+      /*clickableLinks*/ true,
+      /*columnColorMode*/ 'type',
+      /*columnColorPalette*/ 'default',
+      /*showTrailingEmptyRow*/ false
+    );
+    assert.strictEqual(chunks.length, 0);
+    assert.ok(tableHtml.includes('data-row="0" data-col="0"'));
+  });
+
   it('sizes serial index column from total row count for chunked data', () => {
     const rows: string[][] = Array.from({ length: 12345 }, (_, i) => [String(i + 1), 'x']);
     const { tableHtml, chunks } = CsvEditorProvider.__test.generateTableAndChunksRaw(rows, /*treatHeader*/ false, /*addSerialIndex*/ true, /*hiddenRows*/ 0);