rules:
- id: assigned-undefined
  languages:
  - javascript
  - typescript
  message: '`undefined` is not a reserved keyword in Javascript, so this is "valid" Javascript but highly confusing and likely
    to result in bugs.'
  pattern-either:
  - pattern: undefined = $X;
  - pattern: var undefined = $X;
  - pattern: let undefined = $X;
  - pattern: const undefined = $X;
  severity: WARNING
  metadata:
    category: best-practice
    technology:
    - javascript