ESLint Config Naming

Appearance

Node.js Common Variables ​

  • Filter: ^__(filename|dirname)$
  • Allowed: Any format (format checking disabled)

Why This Rule ​

Node.js provides special global variables __filename and __dirname that don't follow standard JavaScript naming conventions. These are built-in variables with double underscore prefixes that indicate the current file's absolute path and directory path respectively.

Node.js conventions:

ts
// These are built-in Node.js variables
console.log(__filename); // WHY: Node.js runtime global — allowed despite underscores
console.log(__dirname); // WHY: Node.js runtime global — allowed despite underscores

Without this exception, ESLint would flag these standard Node.js variables as violations since they use double leading underscores and don't match typical camelCase or UPPER_CASE patterns.

This rule specifically allows these two well-known Node.js variables while maintaining strict naming conventions for all other variables in your codebase.

Common use cases:

  • Resolving relative file paths: path.join(__dirname, '../config')
  • Loading local assets: fs.readFileSync(path.join(__dirname, 'data.json'))
  • Module resolution: require.resolve(__dirname + '/module')
  • Debugging and logging: console.log('Error in', __filename)

References:

✅ Good ​

ts
const configPath = path.join(__dirname, 'config.json'); // WHY: using __dirname to build paths is common in Node.js
const currentFile = __filename; // WHY: accessing the current filename is valid and allowed by this rule

✅ Not affected ​

These variables are specifically exempted, so there are no "bad" examples - they're always allowed:

ts
// These are always valid
__dirname; // WHY: exempted by rule
__filename; // WHY: exempted by rule