feat(fmt): add ignore patterns matcher

packages/rstack/THIRD_PARTY_NOTICES.md

@@ -2,6 +2,34 @@
 
 This package includes software developed by third parties.
 
+## fast-ignore
+
+This package includes bundled code from [fast-ignore](https://github.com/fabiospampinato/fast-ignore).
+
+License: MIT
+
+The MIT License (MIT)
+
+Copyright (c) 2023-present Fabio Spampinato
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of this software and associated documentation files (the "Software"),
+to deal in the Software without restriction, including without limitation
+the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+
 ## fresh-import
 
 This package includes bundled code from [fresh-import](https://github.com/sapphi-red/fresh-import).

packages/rstack/package.json

@@ -67,6 +67,7 @@
     "@rstest/adapter-rslib": "catalog:",
     "@types/micromatch": "catalog:",
     "@types/node": "catalog:",
+    "fast-ignore": "catalog:",
     "lint-staged": "catalog:",
     "micromatch": "catalog:",
     "rslog": "catalog:",

packages/rstack/src/fmt/ignore.ts

@@ -0,0 +1,12 @@
+import { relative } from 'node:path';
+import fastIgnore from 'fast-ignore';
+import type { ResolvedFmtConfig } from './types.ts';
+
+/** Creates a reusable matcher for config-level ignore patterns. */
+const createFmtIgnoreMatcher = (config: ResolvedFmtConfig): ((filePath: string) => boolean) => {
+  const matches = fastIgnore(config.ignorePatterns.join('\n'));
+
+  return (filePath) => matches(relative(config.rootPath, filePath));
+};
+
+export { createFmtIgnoreMatcher };

packages/rstack/tests/fmt/ignore.test.ts

@@ -0,0 +1,52 @@
+import path from 'node:path';
+import { expect, test } from 'rstack/test';
+import { normalizeFmtConfig } from '../../src/fmt/config.ts';
+import { createFmtIgnoreMatcher } from '../../src/fmt/ignore.ts';
+
+const rootPath = path.join(import.meta.dirname, 'project');
+
+const createMatcher = (ignorePatterns: string[]) =>
+  createFmtIgnoreMatcher(normalizeFmtConfig({ ignorePatterns }, rootPath));
+
+test('matches gitignore patterns relative to the config root', () => {
+  const isIgnored = createMatcher(['dist/', '*.snap', '/root.js', '# comment', '\\#generated.js']);
+
+  expect(isIgnored(path.join(rootPath, 'dist/index.js'))).toBe(true);
+  expect(isIgnored(path.join(rootPath, 'src/data.snap'))).toBe(true);
+  expect(isIgnored(path.join(rootPath, 'root.js'))).toBe(true);
+  expect(isIgnored(path.join(rootPath, 'nested/root.js'))).toBe(false);
+  expect(isIgnored(path.join(rootPath, '#generated.js'))).toBe(true);
+  expect(isIgnored(path.join(rootPath, 'src/index.js'))).toBe(false);
+});
+
+test('applies negated patterns in declaration order', () => {
+  const isIgnored = createMatcher(['*.js', '!src/keep.js']);
+  const isIgnoredAgain = createMatcher(['*.js', '!src/keep.js', 'src/keep.js']);
+  const isReincluded = createMatcher(['dist', '!dist']);
+  const filePath = path.join(rootPath, 'src/keep.js');
+
+  expect(isIgnored(filePath)).toBe(false);
+  expect(isIgnored(path.join(rootPath, 'src/drop.js'))).toBe(true);
+  expect(isIgnoredAgain(filePath)).toBe(true);
+  expect(isReincluded(path.join(rootPath, 'dist'))).toBe(false);
+});
+
+test('does not let explicit files bypass ignore patterns', () => {
+  const isIgnored = createMatcher(['generated/']);
+  const explicitFilePath = path.join(rootPath, 'generated/output.js');
+
+  expect(isIgnored(explicitFilePath)).toBe(true);
+});
+
+test('matches parent directory patterns without validation', () => {
+  const isIgnored = createMatcher(['../shared/*.js']);
+
+  expect(isIgnored(path.join(rootPath, '../shared/index.js'))).toBe(true);
+  expect(isIgnored(path.join(rootPath, 'shared/index.js'))).toBe(false);
+});
+
+test('does not ignore files when no patterns are configured', () => {
+  const isIgnored = createMatcher([]);
+
+  expect(isIgnored(path.join(rootPath, 'src/index.js'))).toBe(false);
+});

pnpm-workspace.yaml

@@ -34,6 +34,7 @@ catalog:
   '@types/react-dom': '^19.2.3'
   '@shikijs/transformers': '^4.3.1'
   'cspell-ban-words': '^0.0.4'
+  'fast-ignore': '2.0.0'
   'happy-dom': '^20.11.1'
   'heading-case': '^1.1.4'
   'lint-staged': '^17.2.0'