import * as plugins from '../plugins.js';
/**
 * A class to convert a given ILetter with invoice data
 * into an XInvoice/XRechnung compliant XML (based on UBL).
 *
 * XRechnung is the German implementation of the European standard EN16931
 * for electronic invoices to the German public sector.
 */
export declare class XInvoiceEncoder {
    constructor();
    /**
     * Creates an XInvoice compliant XML based on the provided letter data.
     */
    createXInvoiceXml(letterArg: plugins.tsclass.business.ILetter): string;
    /**
     * Helper: Map your custom 'unitType' to an ISO code.
     */
    private mapUnitType;
}