Merge pull request #5596 from Tyriar/lint_changes

New npm script to lint only changes

.github/copilot-instructions.md

@@ -26,6 +26,7 @@ npm run build && npm run esbuild # Build all TypeScript and bundle
 - Integration tests: `npm run test-integration` (Playwright across Chrome/Firefox/WebKit)
 - Integration tests by file: `npm run test-integration -- test/playwright/InputHandler.test.ts`. Never use grep to filter tests, it doesn't work
 - Integration tests by addon: `npm run test-integration --suite=addon-search`. Suites always follow the format `addon-<something>`
+- Lint changes: `npm run lint-changes` to lint only changed files, `npm run lint-changes-fix` to fix them
 
 ## Addon Development Pattern
 

bin/lint_changes.js

@@ -0,0 +1,49 @@
+/**
+ * Copyright (c) 2026 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+// @ts-check
+
+const { execSync, spawn } = require('child_process');
+const path = require('path');
+
+const extensions = ['.ts', '.mts'];
+const fix = process.argv.includes('--fix');
+
+// Get uncommitted changed files (staged + unstaged)
+function getChangedFiles() {
+  try {
+    const output = execSync('git diff --name-only --diff-filter=ACMR HEAD', {
+      encoding: 'utf-8',
+      cwd: path.join(__dirname, '..')
+    });
+    return output.split('\n').filter(f => f && extensions.some(ext => f.endsWith(ext)));
+  } catch {
+    return [];
+  }
+}
+
+const files = getChangedFiles();
+
+if (files.length === 0) {
+  console.log('No changed TypeScript files to lint.');
+  process.exit(0);
+}
+
+console.log(`Linting ${files.length} changed file(s)...`);
+
+const eslintArgs = ['--max-warnings', '0'];
+if (fix) {
+  eslintArgs.push('--fix');
+}
+eslintArgs.push(...files);
+
+const eslint = process.platform === 'win32' ? 'eslint.cmd' : 'eslint';
+const child = spawn(eslint, eslintArgs, {
+  stdio: 'inherit',
+  cwd: path.join(__dirname, '..'),
+  shell: process.platform === 'win32'
+});
+
+child.on('close', code => process.exit(code ?? 0));

package.json

@@ -48,6 +48,8 @@
     "test": "npm run test-unit",
     "posttest": "npm run lint",
     "lint": "eslint --max-warnings 0 src/ addons/ demo/",
+    "lint-changes": "node ./bin/lint_changes.js",
+    "lint-changes-fix": "node ./bin/lint_changes.js --fix",
     "lint-fix": "eslint --fix src/ addons/ demo/",
     "lint-api": "eslint --config eslint.config.typings.mjs --max-warnings 0 typings/",
     "test-unit": "node ./bin/test_unit.js",