update

ts/einvoice.ts

@@ -412,6 +412,13 @@ export class EInvoice implements TInvoice {
     try {
       const encoder = EncoderFactory.createEncoder(format);
       const invoice = this.mapToTInvoice();
+      
+      // Import EN16931Validator dynamically to avoid circular dependency
+      const { EN16931Validator } = await import('./formats/validation/en16931.validator.js');
+      
+      // Validate mandatory fields before encoding
+      EN16931Validator.validateMandatoryFields(invoice);
+      
       return await encoder.encode(invoice);
     } catch (error) {
       throw new EInvoiceFormatError(`Failed to encode to ${format}: ${error.message}`, { targetFormat: format });