feat: add 'Run on save' feature to automatically re-run checks on file save

- Introduced a new setting `angularCodeQuality.runOnSave` to enable automatic re-running of relevant tools when files are saved.
- Updated the Problems panel in the background without notifications, supporting `.ts`, `.css`, `.scss`, and `package.json` files.
- Implemented debounce logic to optimize performance during rapid saves.
- Added documentation in CHANGELOG and README for the new feature.

Author: Arul1998

CHANGELOG.md

@@ -2,6 +2,12 @@
 
 All notable changes to the Angular Code Quality Toolkit extension are documented in this file.
 
+## [Unreleased]
+
+### Added
+
+- **Run on save.** New setting `angularCodeQuality.runOnSave` (default off): when enabled, saving a file re-runs the relevant tool and refreshes the Problems panel in the background — saving a `.ts` file re-runs ESLint and ts-prune, a `.css`/`.scss` file re-runs stylelint, and `package.json` re-runs depcheck. Runs are quiet (no notifications) and debounced, so a "Save All" triggers a single run instead of one per file.
+
 ## [0.3.1] - 2026-08-23
 
 Same packaged extension as 0.3.0. Bumped because Open VSX treats versions as immutable — 0.3.0 was published, then deleted, and that identity cannot be reused.

README.md

@@ -92,6 +92,21 @@ To catch unused variables and parameters, add the rule to your ESLint config so
 | `angularCodeQuality.depcheck.ignoreAngularImplicit` | `true` | Hide false "unused" hits for packages Angular uses implicitly (`@angular/*`, `zone.js`, `rxjs`, `tslib`, `typescript`, karma/jasmine, builders). |
 | `angularCodeQuality.depcheck.ignores` | `[]` | Extra packages to hide (`*` wildcard, e.g. `@my-scope/*`). |
 | `angularCodeQuality.revealOutputOnRun` | `false` | Auto-open the Output channel on each run. Off by default — findings go to the Problems panel; enable this only to watch raw tool logs. |
+| `angularCodeQuality.runOnSave` | `false` | Re-run the relevant checks automatically when you save a file (see below). |
+
+---
+
+## Run on save
+
+Set `angularCodeQuality.runOnSave` to `true` and the extension re-runs the relevant tool whenever you save — the Problems panel stays current without you triggering **Run all checks** by hand:
+
+| You save… | It re-runs |
+| --- | --- |
+| a `.ts` file | ESLint + ts-prune |
+| a `.css` / `.scss` file | stylelint |
+| `package.json` | depcheck |
+
+Runs happen **quietly** in the background (no notifications) and are **debounced**, so a "Save All" or a formatter re-saving triggers a single run rather than one per file. Off by default.
 
 ---
 

package.json

@@ -177,6 +177,11 @@
           "type": "boolean",
           "default": false,
           "description": "Reveal the Angular Code Quality output channel automatically each time a command runs. Findings appear in the Problems panel; enable this only if you want to watch the raw tool logs."
+        },
+        "angularCodeQuality.runOnSave": {
+          "type": "boolean",
+          "default": false,
+          "description": "Automatically re-run the relevant checks when you save a file, updating the Problems panel in the background (no notifications). Saving a .ts file re-runs ESLint and ts-prune; a .css/.scss file re-runs stylelint; package.json re-runs depcheck. Runs are debounced so rapid saves trigger a single run."
         }
       }
     }

src/extension.ts

@@ -24,6 +24,7 @@ import {
   defaultProject,
   styleGlobsForProject,
 } from './angularWorkspace';
+import { toolsForSavedFile } from './runOnSave';
 
 const DIAGNOSTIC_SOURCE = 'Angular Code Quality';
 
@@ -812,6 +813,75 @@ function clearAllDiagnostics(): void {
   vscode.window.setStatusBarMessage('Angular Code Quality: cleared all results.', 3000);
 }
 
+// --- Run on save ------------------------------------------------------------
+
+/** Coalesce rapid saves (e.g. Save All, formatters re-saving) into one run. */
+const RUN_ON_SAVE_DEBOUNCE_MS = 800;
+let runOnSaveTimer: ReturnType<typeof setTimeout> | undefined;
+const pendingRunOnSaveTools = new Set<ToolKey>();
+
+/** Invoke a single tool's run quietly (no toast/progress) for background refreshes. */
+async function runToolByKey(tool: ToolKey): Promise<void> {
+  const quiet = { quiet: true };
+  switch (tool) {
+    case 'depcheck':
+      await runDepcheck(quiet);
+      break;
+    case 'ts-prune':
+      await runTsPrune(quiet);
+      break;
+    case 'eslint':
+      await runEslint(quiet);
+      break;
+    case 'stylelint':
+      await runStylelint(quiet);
+      break;
+  }
+}
+
+async function flushRunOnSave(): Promise<void> {
+  runOnSaveTimer = undefined;
+  const tools = [...pendingRunOnSaveTools];
+  pendingRunOnSaveTools.clear();
+  // Run sequentially so several tools don't contend for the same package manager.
+  for (const tool of tools) {
+    await runToolByKey(tool);
+  }
+}
+
+/** Queue the given tools and (re)start the debounce window. */
+function scheduleRunOnSave(tools: ToolKey[]): void {
+  for (const tool of tools) {
+    pendingRunOnSaveTools.add(tool);
+  }
+  if (runOnSaveTimer) {
+    clearTimeout(runOnSaveTimer);
+  }
+  runOnSaveTimer = setTimeout(() => void flushRunOnSave(), RUN_ON_SAVE_DEBOUNCE_MS);
+}
+
+function handleDidSave(document: vscode.TextDocument): void {
+  if (!vscode.workspace.getConfiguration('angularCodeQuality').get<boolean>('runOnSave', false)) {
+    return;
+  }
+  if (document.uri.scheme !== 'file') {
+    return;
+  }
+  const folder = getWorkspaceFolder();
+  if (!folder) {
+    return;
+  }
+  // Only react to files inside the workspace folder.
+  const rel = path.relative(folder.uri.fsPath, document.uri.fsPath);
+  if (rel.startsWith('..') || path.isAbsolute(rel)) {
+    return;
+  }
+  const tools = toolsForSavedFile(document.uri.fsPath);
+  if (tools.length > 0) {
+    scheduleRunOnSave(tools);
+  }
+}
+
 export function activate(context: vscode.ExtensionContext): void {
   const toolKeys: ToolKey[] = ['depcheck', 'ts-prune', 'eslint', 'stylelint'];
   for (const key of toolKeys) {
@@ -838,7 +908,9 @@ export function activate(context: vscode.ExtensionContext): void {
     ),
     vscode.commands.registerCommand('angularCodeQualityToolkit.selectProject', () =>
       selectAngularProject()
-    )
+    ),
+    // Run-on-save: re-run the relevant tool(s) when a file is saved (opt-in).
+    vscode.workspace.onDidSaveTextDocument(handleDidSave)
   );
 
   // Show the active Angular project in the status bar on startup, if any.
@@ -849,6 +921,11 @@ export function activate(context: vscode.ExtensionContext): void {
 }
 
 export function deactivate(): void {
+  if (runOnSaveTimer) {
+    clearTimeout(runOnSaveTimer);
+    runOnSaveTimer = undefined;
+  }
+  pendingRunOnSaveTools.clear();
   outputChannel?.dispose();
   projectStatusBar?.dispose();
   projectStatusBar = undefined;

src/runOnSave.ts

@@ -0,0 +1,29 @@
+import * as path from 'path';
+import { ToolKey } from './diagnostics';
+
+/**
+ * Maps a saved file to the tools that should re-run for it (run-on-save):
+ *
+ *  - `package.json`   -> depcheck (dependency usage can change)
+ *  - `*.ts`           -> ESLint + ts-prune (lint + unused-export analysis)
+ *  - `*.css` / `*.scss` -> stylelint
+ *
+ * Returns an empty array for files no tool cares about (e.g. `.html`, `.md`),
+ * so the caller can cheaply skip scheduling a run.
+ *
+ * Pure and vscode-free so it can be unit-tested without the extension host.
+ */
+export function toolsForSavedFile(filePath: string): ToolKey[] {
+  const base = path.basename(filePath).toLowerCase();
+  if (base === 'package.json') {
+    return ['depcheck'];
+  }
+  const ext = path.extname(base);
+  if (ext === '.ts') {
+    return ['eslint', 'ts-prune'];
+  }
+  if (ext === '.css' || ext === '.scss') {
+    return ['stylelint'];
+  }
+  return [];
+}

src/test/runOnSave.test.ts

@@ -0,0 +1,30 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { toolsForSavedFile } from '../runOnSave';
+
+test('toolsForSavedFile maps package.json to depcheck', () => {
+  assert.deepEqual(toolsForSavedFile('/repo/package.json'), ['depcheck']);
+  // nested package.json (monorepo) still maps by basename
+  assert.deepEqual(toolsForSavedFile('/repo/apps/web/package.json'), ['depcheck']);
+});
+
+test('toolsForSavedFile maps .ts files to eslint + ts-prune', () => {
+  assert.deepEqual(toolsForSavedFile('/repo/src/app/app.component.ts'), ['eslint', 'ts-prune']);
+});
+
+test('toolsForSavedFile maps .css and .scss files to stylelint', () => {
+  assert.deepEqual(toolsForSavedFile('/repo/src/styles.css'), ['stylelint']);
+  assert.deepEqual(toolsForSavedFile('/repo/src/app/app.component.scss'), ['stylelint']);
+});
+
+test('toolsForSavedFile is case-insensitive on extension and name', () => {
+  assert.deepEqual(toolsForSavedFile('/repo/Foo.TS'), ['eslint', 'ts-prune']);
+  assert.deepEqual(toolsForSavedFile('/repo/Styles.SCSS'), ['stylelint']);
+  assert.deepEqual(toolsForSavedFile('/repo/PACKAGE.JSON'), ['depcheck']);
+});
+
+test('toolsForSavedFile returns [] for files no tool handles', () => {
+  assert.deepEqual(toolsForSavedFile('/repo/src/app/app.component.html'), []);
+  assert.deepEqual(toolsForSavedFile('/repo/README.md'), []);
+  assert.deepEqual(toolsForSavedFile('/repo/angular.json'), []);
+});