Analyze the current file `[FILE_PATH]` and perform a comprehensive refactoring. Goals: 1. Modernize the syntax (use modern ES6/TypeScript features, remove obsolete patterns). 2. Improve readability by extracting complex nested logic into small, pure helper functions. 3. Eliminate any 'any' types and replace them with strict TypeScript interfaces. 4. Optimize performance by reducing unnecessary re-renders or loops. 5. Add comprehensive JSDoc comments to all public functions and interfaces. 6. Generate a corresponding Jest unit test file covering the primary edge cases. Do not change the external API signature of the primary exported functions unless absolutely necessary. Explain the major architectural changes you make before providing the code.