/**
 * Checks if the placeholder provided is single or compound and returns either the first two letters,
 * or the initials of the two first words.
 * @param {string} placeholder
 * @return {string} An array with the first two leters of the placeholder, or initials of the
 * first two words in uppercase
 * @example formatPlaceholder('Juan') // returns 'JU'
 * @example formatPlaceholder('Juan Perez') // returns 'JP'
 * @example formatPlaceholder('Juan Perez Rodriguez') // returns 'JP'
 * @example formatPlaceholder('') // returns ''
 */
export declare const formatPlaceholder: (placeholder?: string) => string;