feature: @putout/eslint: improve support of FlatConfig

Author: coderaiser

packages/eslint/eslint.config.js

@@ -0,0 +1,3 @@
+import {recommended} from 'eslint-plugin-putout';
+
+export default recommended;

packages/eslint/eslint.config.mjs

@@ -3,6 +3,8 @@ import process from 'node:process';
 import {loadESLint} from 'eslint';
 import {findUp} from 'find-up';
 
+const {isArray} = Array;
+const maybeArray = (a) => isArray(a) ? a : [a];
 const CWD = process.cwd();
 
 export const getESLint = async ({name, fix, config, overrideConfigFile, loadESLintOverride, find = findUp, findFlat = find, findRC = find}) => {
@@ -61,18 +63,19 @@ async function getOldESLint({cwd, fix, config, overrideConfigFile, loadESLintOve
     return eslint;
 }
 
-async function getFlatESLint({cwd, fix, config, overrideConfigFile, loadESLintOverride = loadESLint}) {
+async function getFlatESLint({cwd, fix, config = [], overrideConfigFile, loadESLintOverride = loadESLint}) {
     const FlatESLint = await loadESLintOverride({
         useFlatConfig: true,
     });
 
     const eslint = new FlatESLint({
         cwd,
         fix,
-        overrideConfig: {
-            ignores: ['!.*'],
-            ...config,
-        },
+        overrideConfig: [
+            ...maybeArray(config), {
+                ignores: ['!.*'],
+            },
+        ],
         ...overrideConfigFile && {
             overrideConfigFile,
         },

packages/eslint/lib/get-eslint.mjs

@@ -33,9 +33,9 @@ test('putout: eslint: get-eslint: config: putout', async (t) => {
     const expected = [{
         cwd: __dirname,
         fix: false,
-        overrideConfig: {
+        overrideConfig: [{
             ignores: ['!.*'],
-        },
+        }],
     }];
 
     t.calledWith(ESLintOverride, expected);
@@ -133,9 +133,9 @@ test('putout: eslint: get-eslint: flat: overrideConfigFile', async (t) => {
     const expected = [{
         cwd: CWD,
         fix: false,
-        overrideConfig: {
+        overrideConfig: [{
             ignores: ['!.*'],
-        },
+        }],
         overrideConfigFile: 'other.config.js',
     }];
 
@@ -166,9 +166,9 @@ test('putout: eslint: get-eslint: flat: no overrides', async (t) => {
     const expected = [{
         cwd: CWD,
         fix: false,
-        overrideConfig: {
+        overrideConfig: [{
             ignores: ['!.*'],
-        },
+        }],
     }];
 
     t.calledWith(ESLintOverride, expected);