/**
 * @name isValid
 * @category Common Helpers
 * @summary Is the given date valid?
 *
 * @description
 * Returns false if argument is Invalid Date and true otherwise.
 * Argument is converted to Date using `toDate`. See [toDate](https://date-fns.org/docs/toDate)
 * Invalid Date is a Date, whose time value is NaN.
 *
 * Time value of Date: http://es5.github.io/#x15.9.1.1
 *
 * @typeParam DateType - The `Date` type, the function operates on. Gets inferred from passed arguments. Allows to use extensions like [`UTCDate`](https://github.com/date-fns/utc).
 *
 * @param date - The date to check
 *
 * @returns The date is valid
 *
 * @example
 * // For the valid date:
 * const result = isValid(new Date(2014, 1, 31))
 * //=> true
 *
 * @example
 * // For the value, convertable into a date:
 * const result = isValid(1393804800000)
 * //=> true
 *
 * @example
 * // For the invalid date:
 * const result = isValid(new Date(''))
 * //=> false
 */
export declare function isValid(date: unknown): boolean;