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# Directory Configuration
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Advanced configuration building for specific directories, supporting both file paths and file:// URLs. Handles config reading, path resolution, and pattern building for monorepo structures.
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## Capabilities
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### matchToFlatDir Function
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Builds ESLint flat config for a specific directory path, automatically reading configuration files and adjusting file patterns with directory prefixes.
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```javascript { .api }
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/**
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 * Builds ESLint flat config for a specific directory path
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 * @param {string|URL} cwd - Current working directory or file URL
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 * @param {string} path - Relative path to directory
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 * @param {Object} [config] - Optional existing config object, reads from directory if not provided
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 * @param {Object} [overrides] - Optional override functions for dependency injection
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 * @returns {Promise<Array<Object>>} Promise resolving to array of ESLint flat config objects
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 */
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async function matchToFlatDir(cwd, path, config, overrides);
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```
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**Parameters:**
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- `cwd` (string|URL): Current working directory or file:// URL (supports import.meta.url)
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- `path` (string): Relative path to the directory containing ESLint configuration
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- `config` (Object, optional): Existing configuration object. If not provided, reads from directory
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- `overrides` (Object, optional): Override functions for dependency injection (currently no public override options available)
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**Returns:**
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Promise resolving to array of ESLint flat config objects with properly prefixed file patterns.
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**Usage Examples:**
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**With File Path:**
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```javascript
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const { matchToFlatDir } = require('@putout/eslint-flat');
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// Using __dirname (CommonJS)
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const config = await matchToFlatDir(__dirname, './packages/putout');
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// The function will:
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// 1. Read eslint config from ./packages/putout directory
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// 2. Prefix all file patterns with **/packages/putout/
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// 3. Return flat config array
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```
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**With File URL (ESM):**
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```javascript
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import { matchToFlatDir } from '@putout/eslint-flat';
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// Using import.meta.url (ESM)
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const config = await matchToFlatDir(import.meta.url, './packages/putout');
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```
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**With Custom Configuration:**
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```javascript
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const { matchToFlatDir } = require('@putout/eslint-flat');
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// Provide config directly instead of reading from directory
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const customConfig = {
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  match: {
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    'bin/*.js': {
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      'n/hashbang': 'off',
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    },
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    'lib/**/*.js': {
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      'complexity': ['error', 10],
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    },
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  },
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};
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const result = await matchToFlatDir(__dirname, './my-package', customConfig);
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// Result will have patterns like:
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// - files: ['**/my-package/bin/*.js']
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// - files: ['**/my-package/lib/**/*.js']
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```
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**In Monorepo ESLint Config:**
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```javascript
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const { safeAlign } = require('eslint-plugin-putout/config');
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const { matchToFlatDir } = require('@putout/eslint-flat');
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module.exports = [
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  ...safeAlign,
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  // Include configuration from specific package
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  ...await matchToFlatDir(__dirname, './packages/putout'),
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  ...await matchToFlatDir(__dirname, './packages/eslint-flat'),
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];
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```
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## Configuration File Resolution
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The function automatically tries to read ESLint configuration in this order:
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1. **Modern flat config files:**
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   - `eslint.config.js`
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   - `eslint.config.cjs`
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   - `eslint.config.mjs`
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2. **Legacy configuration:**
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   - `.eslintrc.json` (converted using ESLint's FlatCompat)
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## Configuration Formats
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**Match Object Format (Simplified):**
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If the config exports a `match` property, it uses the simplified object format:
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```javascript
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// In ./packages/my-package/eslint.config.js
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module.exports = {
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  match: {
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    'src/*.js': {
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      'no-console': 'warn',
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    },
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    'test/*.js': {
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      'no-console': 'off',
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    },
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  },
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};
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```
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**Standard Flat Config Format:**
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If no `match` property, processes as standard ESLint flat config:
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```javascript
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// In ./packages/my-package/eslint.config.js
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module.exports = [
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  {
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    files: ['src/*.js'],
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    rules: {
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      'no-console': 'warn',
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    },
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  },
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  {
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    files: ['test/*.js'],
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    rules: {
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      'no-console': 'off',
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    },
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    ignores: ['test/fixtures/**'],
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  },
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];
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```
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## Path Handling
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**File Pattern Processing:**
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- Automatically prefixes file patterns with `**/directory-path/`
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- Handles both simple patterns and complex glob patterns
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- Preserves function-based file patterns without modification
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**Ignore Pattern Processing:**
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- Processes `ignores` arrays by prefixing with directory path
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- Preserves function-based ignore patterns
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- Only adds `ignores` property if patterns exist
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**URL Support:**
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- Supports both regular directory paths and file:// URLs
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- Automatically converts file:// URLs to file system paths
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- Useful for ESM modules using import.meta.url
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## Error Handling
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- Returns empty array `[]` if no configuration files are found
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- Gracefully handles missing directories
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- Uses try-catch internally to prevent errors from propagating
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- Supports dependency injection via overrides for testing