# Constants date-fns provides with a number of useful constants. ## Usage The constants could be imported from `date-fns/constants` or directly from `date-fns`: ```js import { maxTime } from 'date-fns/constants' import { minTime } from 'date-fns' function isAllowedTime(time) { return time <= maxTime && time >= minTime } ``` ## Constants ### `maxTime` Maximum allowed time: ```js import { maxTime } from 'date-fns' const isValid = 8640000000000001 <= maxTime //=> false new Date(8640000000000001) //=> Invalid Date ``` ### `minTime` Minimum allowed time: ```js import { minTime } from 'date-fns' const isValid = -8640000000000001 >= minTime //=> false new Date(-8640000000000001) //=> Invalid Date ```