snippets-date.js

/**
 * 20. dayOfYear
 * This snippet gets the day of the year from a Date object.
 */
 const dayOfYear = (date) =>
 Math.floor((date - new Date(date.getFullYear(), 0, 0)) / 1000 / 60 / 60 / 24)

dayOfYear(new Date()) // 272

/**
* 43. Get Time From Date
* This snippet can be used to get the time from a Date object as a string.
*/
const getColonTimeFromDate = (date) => date.toTimeString().slice(0, 8)

getColonTimeFromDate(new Date()) // "08:38:00"

/**
* 44. Get Days Between Dates
* This snippet can be used to find the difference in days between two dates.
*/
const getDaysDiffBetweenDates = (dateInitial, dateFinal) =>
 (dateFinal - dateInitial) / (1000 * 3600 * 24)
// or
const getDaysDiffBetweenDates = (date1, date2) =>
 Math.ceil(Math.abs(date1 - date2) / (1000 * 60 * 60 * 24))

getDaysDiffBetweenDates(new Date('2019-01-13'), new Date('2019-01-15')) // 2

/**
* 59. isAfterDate
* This snippet can be used to check whether a date is after another date.
*/
const isAfterDate = (dateA, dateB) => dateA > dateB

isAfterDate(new Date(2010, 10, 21), new Date(2010, 10, 20)) // true

/**
* 62. isBeforeDate
* This snippet can be used to check whether a date is before another date.
*/
const isBeforeDate = (dateA, dateB) => dateA < dateB

isBeforeDate(new Date(2010, 10, 20), new Date(2010, 10, 21)) // true

/**
* 74. isSameDate
* This snippet can be used to check whether two dates are equal.
*/
const isSameDate = (dateA, dateB) => dateA.toISOString() === dateB.toISOString()

isSameDate(new Date(2010, 10, 20), new Date(2010, 10, 20)) // true

/**
* 82. maxDate
* This snippet can be used to get the latest date.
*/
const maxDate = (...dates) => new Date(Math.max.apply(null, ...dates))

const array = [
 new Date(2017, 4, 13),
 new Date(2018, 2, 12),
 new Date(2016, 0, 10),
 new Date(2016, 0, 9),
]
maxDate(array) // 2018-03-11T22:00:00.000Z

/**
* 84. minDate
* This snippet can be used to get the earliest date.
*/
const minDate = (...dates) => new Date(Math.min.apply(null, ...dates))

const array = [
 new Date(2017, 4, 13),
 new Date(2018, 2, 12),
 new Date(2016, 0, 10),
 new Date(2016, 0, 9),
]
minDate(array) // 2016-01-08T22:00:00.000Z

/**
* 122. tomorrow
* This snippet can be used to get a string representation of tomorrow’s date.
*/

const tomorrow = () => {
 let t = new Date()
 t.setDate(t.getDate() + 1)
 return t.toISOString().split('T')[0]
}

tomorrow() // 2019-09-08 (if current date is 2018-09-08)