A pure function that ensures a nested property path exists in an object, creating intermediate objects as needed. Used throughout the codebase for safely setting nested values without mutating the original object. Demonstrates skill in functional programming and defensive coding.

Implements a factory that creates format services by name (case-insensitive with normalization). Each format service implements a common interface (EInvoiceFormat). This pattern allows for easy extension with new formats and decouples the invoice generation logic from specific format implementations. Demonstrates skill in applying the strategy and factory patterns to handle complex format variations.

Transforms spreadsheet data (ODS) to the internal invoice format using a YAML mapping definition. Handles section-based mappings (for repeating groups like invoice lines) and empty value handling. The service is self-contained and relies on reusable utility functions for path manipulation. Demonstrates skill in designing a flexible mapping system that can adapt to different spreadsheet structures while maintaining standards compliance.