feat: add .tab file support and default tab delimiter handling

Author: jonaraphael

README.md

@@ -42,7 +42,7 @@ Working with CSV files shouldn’t be a chore. With CSV, you get:
 - **Preserved CSV Integrity:** All modifications respect CSV formatting—no unwanted extra characters or formatting issues.
 - **Optimized for Performance:** Designed for medium-sized datasets, ensuring a smooth editing experience without compromising on functionality.
 - **Large File Support:** Loads big CSVs in chunks so even large datasets open quickly.
-- **TSV Support:** `.tsv` files are recognized automatically and use tabs as the default separator.
+- **TSV/TAB Support:** `.tsv` and `.tab` files are recognized automatically and use tabs as the default separator.
 
 ---
 
@@ -59,9 +59,9 @@ Cursor (built on VS Code 1.99) and the latest VS Code releases (1.102).
 - Go to the Extensions view (`Ctrl+Shift+X` or `Cmd+Shift+X` on macOS).
 - Search for **CSV** and click **Install**.
 
-### 2. Open a CSV or TSV File
+### 2. Open a CSV, TSV, or TAB File
 
-- Open any `.csv` or `.tsv` file in VS Code.
+- Open any `.csv`, `.tsv`, or `.tab` file in VS Code.
 - The file will automatically load, presenting your data in an interactive grid view.
 
 ### 3. Edit and Navigate
@@ -104,7 +104,7 @@ Per-file (stored by the extension; set via commands):
 
 - First row as header (default `true`) — `CSV: Toggle First Row as Header`
 - Serial index column (default `true`) — `CSV: Toggle Serial Index Column`
-- CSV separator (default inherit: `.tsv` → tab, otherwise comma) — `CSV: Change CSV Separator`
+- CSV separator (default inherit: `.tsv`/`.tab` → tab, otherwise comma) — `CSV: Change CSV Separator`
 - Hide first N rows (default `0`) — `CSV: Hide First N Rows`
 
 ---

package.json

@@ -47,11 +47,14 @@
       {
         "id": "tsv",
         "extensions": [
-          ".tsv"
+          ".tsv",
+          ".tab"
         ],
         "aliases": [
           "TSV",
-          "tsv"
+          "tsv",
+          "TAB",
+          "tab"
         ],
         "configuration": "./language-configuration.json"
       }
@@ -133,6 +136,9 @@
           },
           {
             "filenamePattern": "*.tsv"
+          },
+          {
+            "filenamePattern": "*.tab"
           }
         ]
       }

src/CsvEditorProvider.ts

@@ -1087,7 +1087,8 @@ class CsvEditorController {
     const stored = CsvEditorProvider.getSeparatorForUri(this.context, this.document.uri);
     if (stored && stored.length) return stored;
     // Default inherited from file
-    return this.document?.uri.fsPath.toLowerCase().endsWith('.tsv') ? '\t' : ',';
+    const fsPath = this.document?.uri.fsPath.toLowerCase() || '';
+    return (fsPath.endsWith('.tsv') || fsPath.endsWith('.tab')) ? '\t' : ',';
   }
 
   private getHiddenRows(): number {

src/commands.ts

@@ -41,7 +41,9 @@ export function registerCsvCommands(context: vscode.ExtensionContext) {
       const active = CsvEditorProvider.getActiveProvider();
       if (!active) { vscode.window.showInformationMessage('Open a CSV/TSV file in the CSV editor.'); return; }
       const uri = active.getDocumentUri();
-      const currentSep = CsvEditorProvider.getSeparatorForUri(context, uri) ?? (uri.fsPath.toLowerCase().endsWith('.tsv') ? '\\t' : ',');
+      const uriPath = uri.fsPath.toLowerCase();
+      const defaultSep = (uriPath.endsWith('.tsv') || uriPath.endsWith('.tab')) ? '\\t' : ',';
+      const currentSep = CsvEditorProvider.getSeparatorForUri(context, uri) ?? defaultSep;
       const input = await vscode.window.showInputBox({ prompt: 'Enter new CSV separator (empty to inherit from file)', value: currentSep });
       if (input !== undefined) {
         const sep = input;

src/extension.ts

@@ -32,9 +32,9 @@ export function activate(context: vscode.ExtensionContext) {
             if (viewType === CsvEditorProvider.viewType) return; // already our editor
             if (!uri) return;
             const fsPath = uri.fsPath?.toLowerCase?.() || '';
-            const isCsv = fsPath.endsWith('.csv') || fsPath.endsWith('.tsv');
-            console.log(`[CSV(enable)]: -> eligible=${isCsv}`);
-            if (!isCsv) return;
+            const isCsvLike = fsPath.endsWith('.csv') || fsPath.endsWith('.tsv') || fsPath.endsWith('.tab');
+            console.log(`[CSV(enable)]: -> eligible=${isCsvLike}`);
+            if (!isCsvLike) return;
             candidates.push({ group, groupIndex: gi, tab, tabIndex: ti, uri, wasActive: tab.isActive, wasPreview: tab.isPreview, viewColumn: group.viewColumn });
           });
         });

src/test/separators-and-dates.test.ts

@@ -23,9 +23,12 @@ describe('Separators and date edge cases', () => {
     assert.strictEqual(eff('/tmp/sample.csv', undefined), ',');
     // Default TSV -> '\t'
     assert.strictEqual(eff('/tmp/sample.tsv', undefined), '\t');
+    // Default TAB -> '\t'
+    assert.strictEqual(eff('/tmp/sample.tab', undefined), '\t');
     // Override wins regardless of extension
     assert.strictEqual(eff('/tmp/sample.csv', ';'), ';');
     assert.strictEqual(eff('/tmp/sample.tsv', ';'), ';');
+    assert.strictEqual(eff('/tmp/sample.tab', ';'), ';');
   });
 
   it('isDate handles offsets, time components, and rejects bogus values', () => {
@@ -43,4 +46,3 @@ describe('Separators and date edge cases', () => {
     assert.strictEqual(isDate('42'), false);
   });
 });
-