import type { TypeEmailMessage, TransformerInterface } from '@messagehub/core';
import type { TypeSendGridMessage } from '../Type/Types.js';
/**
 * Transforms a TypeEmailMessage object to a TypeSendGridMessage object.
 */
export declare class ToSendGridEmailMessageTransformer implements TransformerInterface<TypeEmailMessage, TypeSendGridMessage> {
    /**
     * Transforms a TypeEmailMessage into SendGrid's email format.
     *
     * @param {TypeEmailMessage | undefined} message - The custom email message object.
     * @returns {TypeSendGridMessage | undefined} - The transformed email object.
     */
    transform(message: TypeEmailMessage | undefined): TypeSendGridMessage | undefined;
}