import { FromInput, Recipient, RecipientInput } from "../types/email.type";
/**
 * Normalizes various email recipient inputs into an array of `{ name, email }` objects.
 *
 * @param to - Can be:
 *   - A string containing a single email address (`"john@example.com"`)
 *   - A string containing multiple emails separated by commas (`"john@example.com, jane@example.com"`)
 *   - A string in the format "Name <email>" (`"John Doe <john@example.com>"`)
 *   - An array of strings mixing these formats
 *   - An object `{ name: string, email: string }`
 *   - An array of objects `{ name: string, email: string }` or a mix of objects and strings
 *
 * @returns An array of normalized `{ name, email }` objects.
 */
export declare function normalizeRecipients(to: RecipientInput): Recipient[];
/**
 * Normalizes various email from inputs into an object `{ name, email }`.
 *
 * @param to - Can be:
 *   - A string containing a single email address (`"john@example.com"`)
 *   - A string in the format "Name <email>" (`"John Doe <john@example.com>"`)
 *   - An object `{ name: string, email: string }`
 *
 * @returns An array of normalized `{ name, email }` objects.
 */
export declare function normalizeFrom(from: FromInput): Recipient | undefined;
/**
 * Checks if an email address is valid
 * @param email The email address to validate
 * @returns true if the email is valid, false otherwise
 */
export declare const isValidEmail: (email: string) => boolean;
/**
 * Filters out recipients with invalid email addresses
 * @param recipients List of recipients
 * @returns List of recipients with invalid email addresses
 */
export declare const checkValidityOfEmails: (recipients: Recipient[]) => Recipient[];