feature: @putout/eslint-flat: add support of FlatConfig

packages/eslint-flat/lib/flat.js

@@ -1,26 +1,9 @@
 'use strict';
 
-const process = require('node:process');
-const {join} = require('node:path');
+const {matchToFlatDir} = require('./match-flat-to-dir');
 const {entries} = Object;
 
-const CWD = process.cwd();
-
-module.exports.matchToFlatDir = (path, config) => {
-    const configPath = join(CWD, path, 'eslint.config.js');
-    const {match} = config || require(configPath);
-
-    const result = [];
-
-    for (const [name, rules] of entries(match)) {
-        result.push({
-            files: ['**/' + join(path, name)],
-            rules,
-        });
-    }
-
-    return result;
-};
+module.exports.matchToFlatDir = matchToFlatDir;
 
 module.exports.matchToFlat = (config) => {
     const result = [];

packages/eslint-flat/lib/flat.spec.js

@@ -49,3 +49,22 @@ test('eslint-flat: matchToFlatDir: require', (t) => {
     t.ok(error);
     t.end();
 });
+
+test('eslint-flat: matchToFlatDir: no match', (t) => {
+    const result = matchToFlatDir('./hello', [{
+        files: ['world'],
+        rules: {
+            semi: 'off',
+        },
+    }]);
+
+    const expected = [{
+        files: ['**/hello/world'],
+        rules: {
+            semi: 'off',
+        },
+    }];
+
+    t.deepEqual(result, expected);
+    t.end();
+});

packages/eslint-flat/lib/match-flat-to-dir.js

@@ -0,0 +1,45 @@
+'use strict';
+
+const process = require('node:process');
+const {join} = require('node:path');
+const {entries} = Object;
+const CWD = process.cwd();
+
+module.exports.matchToFlatDir = (path, config) => {
+    const configPath = join(CWD, path, 'eslint.config.js');
+    const flatConfig = config || require(configPath);
+    const {match} = flatConfig;
+
+    if (match)
+        return parseMatch(path, match);
+
+    return parseFlatConfig(path, flatConfig);
+};
+
+function parseFlatConfig(path, flatConfig) {
+    const result = [];
+
+    for (const {files, rules} of flatConfig) {
+        const [name] = files;
+
+        result.push({
+            files: ['**/' + join(path, name)],
+            rules,
+        });
+    }
+
+    return result;
+}
+
+function parseMatch(path, match) {
+    const result = [];
+
+    for (const [name, rules] of entries(match)) {
+        result.push({
+            files: ['**/' + join(path, name)],
+            rules,
+        });
+    }
+
+    return result;
+}