Configuration files should accurately reflect the actual requirements and characteristics of your codebase. When setting up TypeScript configurations: 1. **Match language settings to feature usage**: Ensure settings like `target` and `lib` correctly align with the ECMAScript features your code actually uses. ```json // Good: Correctly specified to support Array.prototype.includes { "compilerOptions": { "target": "es2015", "lib": ["es2016", "dom"] } } // Bad: Using inconsistent or inappropriate settings { "compilerOptions": { "target": "es2015", "lib": ["esnext", "dom"] // Too broad, or "es2015" would be too restrictive } } ``` 2. **Create modular configurations**: Maintain separate configuration files for different parts of the project instead of overloading a single configuration file. This provides better control over component-specific settings. For example, consider creating a separate tsconfig for private packages rather than adding them to the root configuration's include paths.