/**
 * The validator function returns
 * - input number for number or strings that can be parsed to a number
 * - 0 for other
 *
 * @param {any} initialValue
 *              Value to be validated
 *
 * @return {number}
 *         input number or 0 for wrong input
 *
 * @example
 *        const validatedInitialValue = validateInitialValue(initialValue);
 */
export declare const validateInitialValue: (initialValue: any) => any;