Add latest changes from gitlab-org/gitlab@14-0-stable-eev14.0.0-rc42

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diff --git a/app/assets/javascripts/lib/utils/datetime/date_calculation_utility.js b/app/assets/javascripts/lib/utils/datetime/date_calculation_utility.js
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+import { isNumber } from 'lodash';
+import { __, n__ } from '../../../locale';
+import { getDayName, parseSeconds } from './date_format_utility';
+
+const DAYS_IN_WEEK = 7;
+export const SECONDS_IN_DAY = 86400;
+export const MILLISECONDS_IN_DAY = 24 * 60 * 60 * 1000;
+
+/**
+ * This method allows you to create new Date instance from existing
+ * date instance without keeping the reference.
+ *
+ * @param {Date} date
+ */
+export const newDate = (date) => (date instanceof Date ? new Date(date.getTime()) : new Date());
+
+/**
+ * Returns number of days in a month for provided date.
+ * courtesy: https://stacko(verflow.com/a/1185804/414749
+ *
+ * @param {Date} date
+ */
+export const totalDaysInMonth = (date) => {
+  if (!date) {
+    return 0;
+  }
+  return new Date(date.getFullYear(), date.getMonth() + 1, 0).getDate();
+};
+
+/**
+ * Returns number of days in a quarter from provided
+ * months array.
+ *
+ * @param {Array} quarter
+ */
+export const totalDaysInQuarter = (quarter) =>
+  quarter.reduce((acc, month) => acc + totalDaysInMonth(month), 0);
+
+/**
+ * Returns list of Dates referring to Sundays of the month
+ * based on provided date
+ *
+ * @param {Date} date
+ */
+export const getSundays = (date) => {
+  if (!date) {
+    return [];
+  }
+
+  const daysToSunday = [
+    __('Saturday'),
+    __('Friday'),
+    __('Thursday'),
+    __('Wednesday'),
+    __('Tuesday'),
+    __('Monday'),
+    __('Sunday'),
+  ];
+
+  const month = date.getMonth();
+  const year = date.getFullYear();
+  const sundays = [];
+  const dateOfMonth = new Date(year, month, 1);
+
+  while (dateOfMonth.getMonth() === month) {
+    const dayName = getDayName(dateOfMonth);
+    if (dayName === __('Sunday')) {
+      sundays.push(new Date(dateOfMonth.getTime()));
+    }
+
+    const daysUntilNextSunday = daysToSunday.indexOf(dayName) + 1;
+    dateOfMonth.setDate(dateOfMonth.getDate() + daysUntilNextSunday);
+  }
+
+  return sundays;
+};
+
+/**
+ * Returns list of Dates representing a timeframe of months from startDate and length
+ * This method also supports going back in time when `length` is negative number
+ *
+ * @param {Date} initialStartDate
+ * @param {Number} length
+ */
+export const getTimeframeWindowFrom = (initialStartDate, length) => {
+  if (!(initialStartDate instanceof Date) || !length) {
+    return [];
+  }
+
+  const startDate = newDate(initialStartDate);
+  const moveMonthBy = length > 0 ? 1 : -1;
+
+  startDate.setDate(1);
+  startDate.setHours(0, 0, 0, 0);
+
+  // Iterate and set date for the size of length
+  // and push date reference to timeframe list
+  const timeframe = new Array(Math.abs(length)).fill().map(() => {
+    const currentMonth = startDate.getTime();
+    startDate.setMonth(startDate.getMonth() + moveMonthBy);
+    return new Date(currentMonth);
+  });
+
+  // Change date of last timeframe item to last date of the month
+  // when length is positive
+  if (length > 0) {
+    timeframe[timeframe.length - 1].setDate(totalDaysInMonth(timeframe[timeframe.length - 1]));
+  }
+
+  return timeframe;
+};
+
+/**
+ * Returns count of day within current quarter from provided date
+ * and array of months for the quarter
+ *
+ * Eg;
+ *   If date is 15 Feb 2018
+ *   and quarter is [Jan, Feb, Mar]
+ *
+ *   Then 15th Feb is 46th day of the quarter
+ *   Where 31 (days in Jan) + 15 (date of Feb).
+ *
+ * @param {Date} date
+ * @param {Array} quarter
+ */
+export const dayInQuarter = (date, quarter) => {
+  const dateValues = {
+    date: date.getDate(),
+    month: date.getMonth(),
+  };
+
+  return quarter.reduce((acc, month) => {
+    if (dateValues.month > month.getMonth()) {
+      return acc + totalDaysInMonth(month);
+    } else if (dateValues.month === month.getMonth()) {
+      return acc + dateValues.date;
+    }
+    return acc + 0;
+  }, 0);
+};
+
+export const millisecondsPerDay = 1000 * 60 * 60 * 24;
+
+export const getDayDifference = (a, b) => {
+  const date1 = Date.UTC(a.getFullYear(), a.getMonth(), a.getDate());
+  const date2 = Date.UTC(b.getFullYear(), b.getMonth(), b.getDate());
+
+  return Math.floor((date2 - date1) / millisecondsPerDay);
+};
+
+/**
+ * Calculates the milliseconds between now and a given date string.
+ * The result cannot become negative.
+ *
+ * @param endDate date string that the time difference is calculated for
+ * @return {Number} number of milliseconds remaining until the given date
+ */
+export const calculateRemainingMilliseconds = (endDate) => {
+  const remainingMilliseconds = new Date(endDate).getTime() - Date.now();
+  return Math.max(remainingMilliseconds, 0);
+};
+
+/**
+ * Subtracts a given number of days from a given date and returns the new date.
+ *
+ * @param {Date} date the date that we will substract days from
+ * @param {Number} daysInPast number of days that are subtracted from a given date
+ * @returns {Date} Date in past as Date object
+ */
+export const getDateInPast = (date, daysInPast) =>
+  new Date(newDate(date).setDate(date.getDate() - daysInPast));
+
+/**
+ * Adds a given number of days to a given date and returns the new date.
+ *
+ * @param {Date} date the date that we will add days to
+ * @param {Number} daysInFuture number of days that are added to a given date
+ * @returns {Date} Date in future as Date object
+ */
+export const getDateInFuture = (date, daysInFuture) =>
+  new Date(newDate(date).setDate(date.getDate() + daysInFuture));
+
+/**
+ * Checks if a given date-instance was created with a valid date
+ *
+ * @param  {Date} date
+ * @returns boolean
+ */
+export const isValidDate = (date) => date instanceof Date && !Number.isNaN(date.getTime());
+
+/*
+ * Appending T00:00:00 makes JS assume local time and prevents it from shifting the date
+ * to match the user's time zone. We want to display the date in server time for now, to
+ * be consistent with the "edit issue -> due date" UI.
+ */
+
+export const newDateAsLocaleTime = (date) => {
+  const suffix = 'T00:00:00';
+  return new Date(`${date}${suffix}`);
+};
+
+export const beginOfDayTime = 'T00:00:00Z';
+export const endOfDayTime = 'T23:59:59Z';
+
+/**
+ * @param {Date} d1
+ * @param {Date} d2
+ * @param {Function} formatter
+ * @return {Any[]} an array of formatted dates between 2 given dates (including start&end date)
+ */
+export const getDatesInRange = (d1, d2, formatter = (x) => x) => {
+  if (!(d1 instanceof Date) || !(d2 instanceof Date)) {
+    return [];
+  }
+  let startDate = d1.getTime();
+  const endDate = d2.getTime();
+  const oneDay = 24 * 3600 * 1000;
+  const range = [d1];
+
+  while (startDate < endDate) {
+    startDate += oneDay;
+    range.push(new Date(startDate));
+  }
+
+  return range.map(formatter);
+};
+
+/**
+ * Converts the supplied number of seconds to milliseconds.
+ *
+ * @param {Number} seconds
+ * @return {Number} number of milliseconds
+ */
+export const secondsToMilliseconds = (seconds) => seconds * 1000;
+
+/**
+ * Converts the supplied number of seconds to days.
+ *
+ * @param {Number} seconds
+ * @return {Number} number of days
+ */
+export const secondsToDays = (seconds) => Math.round(seconds / 86400);
+
+/**
+ * Converts a numeric utc offset in seconds to +/- hours
+ * ie -32400 => -9 hours
+ * ie -12600 => -3.5 hours
+ *
+ * @param {Number} offset UTC offset in seconds as a integer
+ *
+ * @return {String} the + or - offset in hours
+ */
+export const secondsToHours = (offset) => {
+  const parsed = parseInt(offset, 10);
+  if (Number.isNaN(parsed) || parsed === 0) {
+    return `0`;
+  }
+  const num = offset / 3600;
+  return parseInt(num, 10) !== num ? num.toFixed(1) : num;
+};
+
+/**
+ * Returns the date `n` days after the date provided
+ *
+ * @param {Date} date the initial date
+ * @param {Number} numberOfDays number of days after
+ * @param {Object} [options={}] Additional options for this calculation
+ * @param {boolean} [options.utc=false] Performs the calculation using UTC dates.
+ * This will cause Daylight Saving Time to be ignored. Defaults to `false`
+ * if not provided, which causes the calculation to be performed in the
+ * user's timezone.
+ *
+ * @return {Date} A `Date` object `n` days after the provided `Date`
+ */
+export const nDaysAfter = (date, numberOfDays, { utc = false } = {}) => {
+  const clone = newDate(date);
+
+  const cloneValue = utc
+    ? clone.setUTCDate(date.getUTCDate() + numberOfDays)
+    : clone.setDate(date.getDate() + numberOfDays);
+
+  return new Date(cloneValue);
+};
+
+/**
+ * Returns the date `n` days before the date provided
+ *
+ * @param {Date} date the initial date
+ * @param {Number} numberOfDays number of days before
+ * @param {Object} [options={}] Additional options for this calculation
+ * @param {boolean} [options.utc=false] Performs the calculation using UTC dates.
+ * This will cause Daylight Saving Time to be ignored. Defaults to `false`
+ * if not provided, which causes the calculation to be performed in the
+ * user's timezone.
+ * @return {Date} A `Date` object `n` days before the provided `Date`
+ */
+export const nDaysBefore = (date, numberOfDays, options) =>
+  nDaysAfter(date, -numberOfDays, options);
+
+/**
+ * Returns the date `n` months after the date provided
+ *
+ * @param {Date} date the initial date
+ * @param {Number} numberOfMonths number of months after
+ * @param {Object} [options={}] Additional options for this calculation
+ * @param {boolean} [options.utc=false] Performs the calculation using UTC dates.
+ * This will cause Daylight Saving Time to be ignored. Defaults to `false`
+ * if not provided, which causes the calculation to be performed in the
+ * user's timezone.
+ *
+ * @return {Date} A `Date` object `n` months after the provided `Date`
+ */
+export const nMonthsAfter = (date, numberOfMonths, { utc = false } = {}) => {
+  const clone = newDate(date);
+
+  const cloneValue = utc
+    ? clone.setUTCMonth(date.getUTCMonth() + numberOfMonths)
+    : clone.setMonth(date.getMonth() + numberOfMonths);
+
+  return new Date(cloneValue);
+};
+
+/**
+ * Returns the date `n` months before the date provided
+ *
+ * @param {Date} date the initial date
+ * @param {Number} numberOfMonths number of months before
+ * @param {Object} [options={}] Additional options for this calculation
+ * @param {boolean} [options.utc=false] Performs the calculation using UTC dates.
+ * This will cause Daylight Saving Time to be ignored. Defaults to `false`
+ * if not provided, which causes the calculation to be performed in the
+ * user's timezone.
+ *
+ * @return {Date} A `Date` object `n` months before the provided `Date`
+ */
+export const nMonthsBefore = (date, numberOfMonths, options) =>
+  nMonthsAfter(date, -numberOfMonths, options);
+
+/**
+ * Returns the date `n` weeks after the date provided
+ *
+ * @param {Date} date the initial date
+ * @param {Number} numberOfWeeks number of weeks after
+ * @param {Object} [options={}] Additional options for this calculation
+ * @param {boolean} [options.utc=false] Performs the calculation using UTC dates.
+ * This will cause Daylight Saving Time to be ignored. Defaults to `false`
+ * if not provided, which causes the calculation to be performed in the
+ * user's timezone.
+ *
+ * @return {Date} A `Date` object `n` weeks after the provided `Date`
+ */
+export const nWeeksAfter = (date, numberOfWeeks, options) =>
+  nDaysAfter(date, DAYS_IN_WEEK * numberOfWeeks, options);
+
+/**
+ * Returns the date `n` weeks before the date provided
+ *
+ * @param {Date} date the initial date
+ * @param {Number} numberOfWeeks number of weeks before
+ * @param {Object} [options={}] Additional options for this calculation
+ * @param {boolean} [options.utc=false] Performs the calculation using UTC dates.
+ * This will cause Daylight Saving Time to be ignored. Defaults to `false`
+ * if not provided, which causes the calculation to be performed in the
+ * user's timezone.
+ *
+ * @return {Date} A `Date` object `n` weeks before the provided `Date`
+ */
+export const nWeeksBefore = (date, numberOfWeeks, options) =>
+  nWeeksAfter(date, -numberOfWeeks, options);
+
+/**
+ * Returns the date `n` years after the date provided.
+ *
+ * @param {Date} date the initial date
+ * @param {Number} numberOfYears number of years after
+ * @return {Date} A `Date` object `n` years after the provided `Date`
+ */
+export const nYearsAfter = (date, numberOfYears) => {
+  const clone = newDate(date);
+  clone.setFullYear(clone.getFullYear() + numberOfYears);
+  return clone;
+};
+
+/**
+ * Returns the date after the date provided
+ *
+ * @param {Date} date the initial date
+ * @param {Object} [options={}] Additional options for this calculation
+ * @param {boolean} [options.utc=false] Performs the calculation using UTC dates.
+ * This will cause Daylight Saving Time to be ignored. Defaults to `false`
+ * if not provided, which causes the calculation to be performed in the
+ * user's timezone.
+ *
+ * @return {Date} the date following the date provided
+ */
+export const dayAfter = (date, options) => nDaysAfter(date, 1, options);
+
+/**
+ * A utility function which computes the difference in seconds
+ * between 2 dates.
+ *
+ * @param {Date} startDate the start date
+ * @param {Date} endDate the end date
+ *
+ * @return {Int} the difference in seconds
+ */
+export const differenceInSeconds = (startDate, endDate) => {
+  return (endDate.getTime() - startDate.getTime()) / 1000;
+};
+
+/**
+ * A utility function which computes the difference in months
+ * between 2 dates.
+ *
+ * @param {Date} startDate the start date
+ * @param {Date} endDate the end date
+ *
+ * @return {Int} the difference in months
+ */
+export const differenceInMonths = (startDate, endDate) => {
+  const yearDiff = endDate.getYear() - startDate.getYear();
+  const monthDiff = endDate.getMonth() - startDate.getMonth();
+  return monthDiff + 12 * yearDiff;
+};
+
+/**
+ * A utility function which computes the difference in milliseconds
+ * between 2 dates.
+ *
+ * @param {Date|Int} startDate the start date. Can be either a date object or a unix timestamp.
+ * @param {Date|Int} endDate the end date. Can be either a date object or a unix timestamp. Defaults to now.
+ *
+ * @return {Int} the difference in milliseconds
+ */
+export const differenceInMilliseconds = (startDate, endDate = Date.now()) => {
+  const startDateInMS = startDate instanceof Date ? startDate.getTime() : startDate;
+  const endDateInMS = endDate instanceof Date ? endDate.getTime() : endDate;
+  return endDateInMS - startDateInMS;
+};
+
+/**
+ * A utility which returns a new date at the first day of the month for any given date.
+ *
+ * @param {Date} date
+ *
+ * @return {Date} the date at the first day of the month
+ */
+export const dateAtFirstDayOfMonth = (date) => new Date(newDate(date).setDate(1));
+
+/**
+ * A utility function which checks if two dates match.
+ *
+ * @param {Date|Int} date1 Can be either a date object or a unix timestamp.
+ * @param {Date|Int} date2 Can be either a date object or a unix timestamp.
+ *
+ * @return {Boolean} true if the dates match
+ */
+export const datesMatch = (date1, date2) => differenceInMilliseconds(date1, date2) === 0;
+
+/**
+ * A utility function which checks if two date ranges overlap.
+ *
+ * @param {Object} givenPeriodLeft - the first period to compare.
+ * @param {Object} givenPeriodRight - the second period to compare.
+ * @returns {Object} { overlap: number of days the overlap is present, overlapStartDate: the start date of the overlap in time format, overlapEndDate: the end date of the overlap in time format }
+ * @throws {Error} Uncaught Error: Invalid period
+ *
+ * @example
+ * getOverlappingDaysInPeriods(
+ *   { start: new Date(2021, 0, 11), end: new Date(2021, 0, 13) },
+ *   { start: new Date(2021, 0, 11), end: new Date(2021, 0, 14) }
+ * ) => { daysOverlap: 2, overlapStartDate: 1610323200000, overlapEndDate: 1610496000000 }
+ *
+ */
+export const getOverlappingDaysInPeriods = (givenPeriodLeft = {}, givenPeriodRight = {}) => {
+  const leftStartTime = new Date(givenPeriodLeft.start).getTime();
+  const leftEndTime = new Date(givenPeriodLeft.end).getTime();
+  const rightStartTime = new Date(givenPeriodRight.start).getTime();
+  const rightEndTime = new Date(givenPeriodRight.end).getTime();
+
+  if (!(leftStartTime <= leftEndTime && rightStartTime <= rightEndTime)) {
+    throw new Error(__('Invalid period'));
+  }
+
+  const isOverlapping = leftStartTime < rightEndTime && rightStartTime < leftEndTime;
+
+  if (!isOverlapping) {
+    return { daysOverlap: 0 };
+  }
+
+  const overlapStartDate = Math.max(leftStartTime, rightStartTime);
+  const overlapEndDate = rightEndTime > leftEndTime ? leftEndTime : rightEndTime;
+  const differenceInMs = overlapEndDate - overlapStartDate;
+
+  return {
+    daysOverlap: Math.ceil(differenceInMs / MILLISECONDS_IN_DAY),
+    overlapStartDate,
+    overlapEndDate,
+  };
+};
+
+/**
+ * Mimics the behaviour of the rails distance_of_time_in_words function
+ * https://api.rubyonrails.org/v6.0.1/classes/ActionView/Helpers/DateHelper.html#method-i-distance_of_time_in_words
+ * 0 < -> 29 secs                                         => less than a minute
+ * 30 secs < -> 1 min, 29 secs                            => 1 minute
+ * 1 min, 30 secs < -> 44 mins, 29 secs                   => [2..44] minutes
+ * 44 mins, 30 secs < -> 89 mins, 29 secs                 => about 1 hour
+ * 89 mins, 30 secs < -> 23 hrs, 59 mins, 29 secs         => about[2..24]hours
+ * 23 hrs, 59 mins, 30 secs < -> 41 hrs, 59 mins, 29 secs => 1 day
+ * 41 hrs, 59 mins, 30 secs                               => x days
+ *
+ * @param {Number} seconds
+ * @return {String} approximated time
+ */
+export const approximateDuration = (seconds = 0) => {
+  if (!isNumber(seconds) || seconds < 0) {
+    return '';
+  }
+
+  const ONE_MINUTE_LIMIT = 90; // 1 minute 30s
+  const MINUTES_LIMIT = 2670; // 44 minutes 30s
+  const ONE_HOUR_LIMIT = 5370; // 89 minutes 30s
+  const HOURS_LIMIT = 86370; // 23 hours 59 minutes 30s
+  const ONE_DAY_LIMIT = 151170; // 41 hours 59 minutes 30s
+
+  const { days = 0, hours = 0, minutes = 0 } = parseSeconds(seconds, {
+    daysPerWeek: 7,
+    hoursPerDay: 24,
+    limitToDays: true,
+  });
+
+  if (seconds < 30) {
+    return __('less than a minute');
+  } else if (seconds < MINUTES_LIMIT) {
+    return n__('1 minute', '%d minutes', seconds < ONE_MINUTE_LIMIT ? 1 : minutes);
+  } else if (seconds < HOURS_LIMIT) {
+    return n__('about 1 hour', 'about %d hours', seconds < ONE_HOUR_LIMIT ? 1 : hours);
+  }
+  return n__('1 day', '%d days', seconds < ONE_DAY_LIMIT ? 1 : days);
+};
+
+/**
+ * A utility function which helps creating a date object
+ * for a specific date. Accepts the year, month and day
+ * returning a date object for the given params.
+ *
+ * @param {Int} year the full year as a number i.e. 2020
+ * @param {Int} month the month index i.e. January => 0
+ * @param {Int} day the day as a number i.e. 23
+ *
+ * @return {Date} the date object from the params
+ */
+export const dateFromParams = (year, month, day) => {
+  return new Date(year, month, day);
+};
+
+/**
+ * A utility function which computes a formatted 24 hour
+ * time string from a positive int in the range 0 - 24.
+ *
+ * @param {Int} time a positive Int between 0 and 24
+ *
+ * @returns {String} formatted 24 hour time String
+ */
+export const format24HourTimeStringFromInt = (time) => {
+  if (!Number.isInteger(time) || time < 0 || time > 24) {
+    return '';
+  }
+
+  const formatted24HourString = time > 9 ? `${time}:00` : `0${time}:00`;
+  return formatted24HourString;
+};
+
+/**
+ * A utility function that checks that the date is today
+ *
+ * @param {Date} date
+ *
+ * @return {Boolean} true if provided date is today
+ */
+export const isToday = (date) => {
+  const today = new Date();
+  return (
+    date.getDate() === today.getDate() &&
+    date.getMonth() === today.getMonth() &&
+    date.getFullYear() === today.getFullYear()
+  );
+};
+
+/**
+ * Checks whether the date is in the past.
+ *
+ * @param {Date} date
+ * @return {Boolean} Returns true if the date falls before today, otherwise false.
+ */
+export const isInPast = (date) => !isToday(date) && differenceInMilliseconds(date, Date.now()) > 0;
+
+/**
+ * Checks whether the date is in the future.
+ * .
+ * @param {Date} date
+ * @return {Boolean} Returns true if the date falls after today, otherwise false.
+ */
+export const isInFuture = (date) =>
+  !isToday(date) && differenceInMilliseconds(Date.now(), date) > 0;
+
+/**
+ * Checks whether dateA falls before dateB.
+ *
+ * @param {Date} dateA
+ * @param {Date} dateB
+ * @return {Boolean} Returns true if dateA falls before dateB, otherwise false
+ */
+export const fallsBefore = (dateA, dateB) => differenceInMilliseconds(dateA, dateB) > 0;
+
+/**
+ * Removes the time component of the date.
+ *
+ * @param {Date} date
+ * @return {Date} Returns a clone of the date with the time set to midnight
+ */
+export const removeTime = (date) => {
+  const clone = newDate(date);
+  clone.setHours(0, 0, 0, 0);
+  return clone;
+};
+
+/**
+ * Returns the start of the provided day
+ *
+ * @param {Object} [options={}] Additional options for this calculation
+ * @param {boolean} [options.utc=false] Performs the calculation using UTC time.
+ * If `true`, the time returned will be midnight UTC. If `false` (the default)
+ * the time returned will be midnight in the user's local time.
+ *
+ * @returns {Date} A new `Date` object that represents the start of the day
+ * of the provided date
+ */
+export const getStartOfDay = (date, { utc = false } = {}) => {
+  const clone = newDate(date);
+
+  const cloneValue = utc ? clone.setUTCHours(0, 0, 0, 0) : clone.setHours(0, 0, 0, 0);
+
+  return new Date(cloneValue);
+};
+
+/**
+ * Returns the start of the current week against the provide date
+ *
+ * @param {Date} date The current date instance to calculate against
+ * @param {Object} [options={}] Additional options for this calculation
+ * @param {boolean} [options.utc=false] Performs the calculation using UTC time.
+ * If `true`, the time returned will be midnight UTC. If `false` (the default)
+ * the time returned will be midnight in the user's local time.
+ *
+ * @returns {Date} A new `Date` object that represents the start of the current week
+ * of the provided date
+ */
+export const getStartOfWeek = (date, { utc = false } = {}) => {
+  const cloneValue = utc
+    ? new Date(date.setUTCHours(0, 0, 0, 0))
+    : new Date(date.setHours(0, 0, 0, 0));
+
+  const diff = cloneValue.getDate() - cloneValue.getDay() + (cloneValue.getDay() === 0 ? -6 : 1);
+
+  return new Date(date.setDate(diff));
+};
+
+/**
+ * Calculates the time remaining from today in words in the format
+ * `n days/weeks/months/years remaining`.
+ *
+ * @param {Date} date A date in future
+ * @return {String} The time remaining in the format `n days/weeks/months/years remaining`
+ */
+export const getTimeRemainingInWords = (date) => {
+  const today = removeTime(new Date());
+  const dateInFuture = removeTime(date);
+
+  const oneWeekFromNow = nWeeksAfter(today, 1);
+  const oneMonthFromNow = nMonthsAfter(today, 1);
+  const oneYearFromNow = nYearsAfter(today, 1);
+
+  if (fallsBefore(dateInFuture, oneWeekFromNow)) {
+    const days = getDayDifference(today, dateInFuture);
+    return n__('1 day remaining', '%d days remaining', days);
+  }
+
+  if (fallsBefore(dateInFuture, oneMonthFromNow)) {
+    const weeks = Math.floor(getDayDifference(today, dateInFuture) / 7);
+    return n__('1 week remaining', '%d weeks remaining', weeks);
+  }
+
+  if (fallsBefore(dateInFuture, oneYearFromNow)) {
+    const months = differenceInMonths(today, dateInFuture);
+    return n__('1 month remaining', '%d months remaining', months);
+  }
+
+  const years = dateInFuture.getFullYear() - today.getFullYear();
+  return n__('1 year remaining', '%d years remaining', years);
+};
diff --git a/app/assets/javascripts/lib/utils/datetime/date_format_utility.js b/app/assets/javascripts/lib/utils/datetime/date_format_utility.js
new file mode 100644
index 00000000000..246f290a90a
--- /dev/null
+++ b/app/assets/javascripts/lib/utils/datetime/date_format_utility.js
@@ -0,0 +1,260 @@
+import dateFormat from 'dateformat';
+import { isString, mapValues, reduce } from 'lodash';
+import { s__, n__, __ } from '../../../locale';
+
+/**
+ * Returns i18n month names array.
+ * If `abbreviated` is provided, returns abbreviated
+ * name.
+ *
+ * @param {Boolean} abbreviated
+ */
+export const getMonthNames = (abbreviated) => {
+  if (abbreviated) {
+    return [
+      s__('Jan'),
+      s__('Feb'),
+      s__('Mar'),
+      s__('Apr'),
+      s__('May'),
+      s__('Jun'),
+      s__('Jul'),
+      s__('Aug'),
+      s__('Sep'),
+      s__('Oct'),
+      s__('Nov'),
+      s__('Dec'),
+    ];
+  }
+  return [
+    s__('January'),
+    s__('February'),
+    s__('March'),
+    s__('April'),
+    s__('May'),
+    s__('June'),
+    s__('July'),
+    s__('August'),
+    s__('September'),
+    s__('October'),
+    s__('November'),
+    s__('December'),
+  ];
+};
+
+/**
+ * Returns month name based on provided date.
+ *
+ * @param {Date} date
+ * @param {Boolean} abbreviated
+ */
+export const monthInWords = (date, abbreviated = false) => {
+  if (!date) {
+    return '';
+  }
+
+  return getMonthNames(abbreviated)[date.getMonth()];
+};
+
+export const dateInWords = (date, abbreviated = false, hideYear = false) => {
+  if (!date) return date;
+
+  const month = date.getMonth();
+  const year = date.getFullYear();
+
+  const monthName = getMonthNames(abbreviated)[month];
+
+  if (hideYear) {
+    return `${monthName} ${date.getDate()}`;
+  }
+
+  return `${monthName} ${date.getDate()}, ${year}`;
+};
+
+/**
+ * Similar to `timeIntervalInWords`, but rounds the return value
+ * to 1/10th of the largest time unit. For example:
+ *
+ * 30 => 30 seconds
+ * 90 => 1.5 minutes
+ * 7200 => 2 hours
+ * 86400 => 1 day
+ * ... etc.
+ *
+ * The largest supported unit is "days".
+ *
+ * @param {Number} intervalInSeconds The time interval in seconds
+ * @returns {String} A humanized description of the time interval
+ */
+export const humanizeTimeInterval = (intervalInSeconds) => {
+  if (intervalInSeconds < 60 /* = 1 minute */) {
+    const seconds = Math.round(intervalInSeconds * 10) / 10;
+    return n__('%d second', '%d seconds', seconds);
+  } else if (intervalInSeconds < 3600 /* = 1 hour */) {
+    const minutes = Math.round(intervalInSeconds / 6) / 10;
+    return n__('%d minute', '%d minutes', minutes);
+  } else if (intervalInSeconds < 86400 /* = 1 day */) {
+    const hours = Math.round(intervalInSeconds / 360) / 10;
+    return n__('%d hour', '%d hours', hours);
+  }
+
+  const days = Math.round(intervalInSeconds / 8640) / 10;
+  return n__('%d day', '%d days', days);
+};
+
+/**
+ * Returns i18n weekday names array.
+ */
+export const getWeekdayNames = () => [
+  __('Sunday'),
+  __('Monday'),
+  __('Tuesday'),
+  __('Wednesday'),
+  __('Thursday'),
+  __('Friday'),
+  __('Saturday'),
+];
+
+/**
+ * Given a date object returns the day of the week in English
+ * @param {date} date
+ * @returns {String}
+ */
+export const getDayName = (date) => getWeekdayNames()[date.getDay()];
+
+/**
+ * Returns the i18n month name from a given date
+ * @example
+ * formatDateAsMonth(new Date('2020-06-28')) -> 'Jun'
+ * @param  {String} datetime where month is extracted from
+ * @param  {Object} options
+ * @param  {Boolean} options.abbreviated whether to use the abbreviated month string, or not
+ * @return {String} the i18n month name
+ */
+export function formatDateAsMonth(datetime, options = {}) {
+  const { abbreviated = true } = options;
+  const month = new Date(datetime).getMonth();
+  return getMonthNames(abbreviated)[month];
+}
+
+/**
+ * @example
+ * dateFormat('2017-12-05','mmm d, yyyy h:MMtt Z' ) -> "Dec 5, 2017 12:00am UTC"
+ * @param {date} datetime
+ * @param {String} format
+ * @param {Boolean} UTC convert local time to UTC
+ * @returns {String}
+ */
+export const formatDate = (datetime, format = 'mmm d, yyyy h:MMtt Z', utc = false) => {
+  if (isString(datetime) && datetime.match(/\d+-\d+\d+ /)) {
+    throw new Error(__('Invalid date'));
+  }
+  return dateFormat(datetime, format, utc);
+};
+
+/**
+ * Formats milliseconds as timestamp (e.g. 01:02:03).
+ * This takes durations longer than a day into account (e.g. two days would be 48:00:00).
+ *
+ * @param milliseconds
+ * @returns {string}
+ */
+export const formatTime = (milliseconds) => {
+  const remainingSeconds = Math.floor(milliseconds / 1000) % 60;
+  const remainingMinutes = Math.floor(milliseconds / 1000 / 60) % 60;
+  const remainingHours = Math.floor(milliseconds / 1000 / 60 / 60);
+  let formattedTime = '';
+  if (remainingHours < 10) formattedTime += '0';
+  formattedTime += `${remainingHours}:`;
+  if (remainingMinutes < 10) formattedTime += '0';
+  formattedTime += `${remainingMinutes}:`;
+  if (remainingSeconds < 10) formattedTime += '0';
+  formattedTime += remainingSeconds;
+  return formattedTime;
+};
+
+/**
+ * Port of ruby helper time_interval_in_words.
+ *
+ * @param  {Number} seconds
+ * @return {String}
+ */
+export const timeIntervalInWords = (intervalInSeconds) => {
+  const secondsInteger = parseInt(intervalInSeconds, 10);
+  const minutes = Math.floor(secondsInteger / 60);
+  const seconds = secondsInteger - minutes * 60;
+  const secondsText = n__('%d second', '%d seconds', seconds);
+  return minutes >= 1
+    ? [n__('%d minute', '%d minutes', minutes), secondsText].join(' ')
+    : secondsText;
+};
+
+/**
+ * Accepts a timeObject (see parseSeconds) and returns a condensed string representation of it
+ * (e.g. '1w 2d 3h 1m' or '1h 30m'). Zero value units are not included.
+ * If the 'fullNameFormat' param is passed it returns a non condensed string eg '1 week 3 days'
+ */
+export const stringifyTime = (timeObject, fullNameFormat = false) => {
+  const reducedTime = reduce(
+    timeObject,
+    (memo, unitValue, unitName) => {
+      const isNonZero = Boolean(unitValue);
+
+      if (fullNameFormat && isNonZero) {
+        // Remove traling 's' if unit value is singular
+        const formattedUnitName = unitValue > 1 ? unitName : unitName.replace(/s$/, '');
+        return `${memo} ${unitValue} ${formattedUnitName}`;
+      }
+
+      return isNonZero ? `${memo} ${unitValue}${unitName.charAt(0)}` : memo;
+    },
+    '',
+  ).trim();
+  return reducedTime.length ? reducedTime : '0m';
+};
+
+/**
+ * Accepts seconds and returns a timeObject { weeks: #, days: #, hours: #, minutes: # }
+ * Seconds can be negative or positive, zero or non-zero. Can be configured for any day
+ * or week length.
+ */
+export const parseSeconds = (
+  seconds,
+  { daysPerWeek = 5, hoursPerDay = 8, limitToHours = false, limitToDays = false } = {},
+) => {
+  const DAYS_PER_WEEK = daysPerWeek;
+  const HOURS_PER_DAY = hoursPerDay;
+  const SECONDS_PER_MINUTE = 60;
+  const MINUTES_PER_HOUR = 60;
+  const MINUTES_PER_WEEK = DAYS_PER_WEEK * HOURS_PER_DAY * MINUTES_PER_HOUR;
+  const MINUTES_PER_DAY = HOURS_PER_DAY * MINUTES_PER_HOUR;
+
+  const timePeriodConstraints = {
+    weeks: MINUTES_PER_WEEK,
+    days: MINUTES_PER_DAY,
+    hours: MINUTES_PER_HOUR,
+    minutes: 1,
+  };
+
+  if (limitToDays || limitToHours) {
+    timePeriodConstraints.weeks = 0;
+  }
+
+  if (limitToHours) {
+    timePeriodConstraints.days = 0;
+  }
+
+  let unorderedMinutes = Math.abs(seconds / SECONDS_PER_MINUTE);
+
+  return mapValues(timePeriodConstraints, (minutesPerPeriod) => {
+    if (minutesPerPeriod === 0) {
+      return 0;
+    }
+
+    const periodCount = Math.floor(unorderedMinutes / minutesPerPeriod);
+
+    unorderedMinutes -= periodCount * minutesPerPeriod;
+
+    return periodCount;
+  });
+};
diff --git a/app/assets/javascripts/lib/utils/datetime/pikaday_utility.js b/app/assets/javascripts/lib/utils/datetime/pikaday_utility.js
new file mode 100644
index 00000000000..63542ddbb6a
--- /dev/null
+++ b/app/assets/javascripts/lib/utils/datetime/pikaday_utility.js
@@ -0,0 +1,28 @@
+export const pad = (val, len = 2) => `0${val}`.slice(-len);
+
+/**
+ * Formats dates in Pickaday
+ * @param {String} dateString Date in yyyy-mm-dd format
+ * @return {Date} UTC format
+ */
+export const parsePikadayDate = (dateString) => {
+  const parts = dateString.split('-');
+  const year = parseInt(parts[0], 10);
+  const month = parseInt(parts[1] - 1, 10);
+  const day = parseInt(parts[2], 10);
+
+  return new Date(year, month, day);
+};
+
+/**
+ * Used `onSelect` method in pickaday
+ * @param {Date} date UTC format
+ * @return {String} Date formatted in yyyy-mm-dd
+ */
+export const pikadayToString = (date) => {
+  const day = pad(date.getDate());
+  const month = pad(date.getMonth() + 1);
+  const year = date.getFullYear();
+
+  return `${year}-${month}-${day}`;
+};
diff --git a/app/assets/javascripts/lib/utils/datetime/timeago_utility.js b/app/assets/javascripts/lib/utils/datetime/timeago_utility.js
new file mode 100644
index 00000000000..512b1f079a1
--- /dev/null
+++ b/app/assets/javascripts/lib/utils/datetime/timeago_utility.js
@@ -0,0 +1,124 @@
+import $ from 'jquery';
+import * as timeago from 'timeago.js';
+import { languageCode, s__ } from '../../../locale';
+import { formatDate } from './date_format_utility';
+
+window.timeago = timeago;
+
+/**
+ * Timeago uses underscores instead of dashes to separate language from country code.
+ *
+ * see https://github.com/hustcc/timeago.js/tree/v3.0.0/locales
+ */
+const timeagoLanguageCode = languageCode().replace(/-/g, '_');
+
+/**
+ * Registers timeago locales
+ */
+const memoizedLocaleRemaining = () => {
+  const cache = [];
+
+  const timeAgoLocaleRemaining = [
+    () => [s__('Timeago|just now'), s__('Timeago|right now')],
+    () => [s__('Timeago|just now'), s__('Timeago|%s seconds remaining')],
+    () => [s__('Timeago|1 minute ago'), s__('Timeago|1 minute remaining')],
+    () => [s__('Timeago|%s minutes ago'), s__('Timeago|%s minutes remaining')],
+    () => [s__('Timeago|1 hour ago'), s__('Timeago|1 hour remaining')],
+    () => [s__('Timeago|%s hours ago'), s__('Timeago|%s hours remaining')],
+    () => [s__('Timeago|1 day ago'), s__('Timeago|1 day remaining')],
+    () => [s__('Timeago|%s days ago'), s__('Timeago|%s days remaining')],
+    () => [s__('Timeago|1 week ago'), s__('Timeago|1 week remaining')],
+    () => [s__('Timeago|%s weeks ago'), s__('Timeago|%s weeks remaining')],
+    () => [s__('Timeago|1 month ago'), s__('Timeago|1 month remaining')],
+    () => [s__('Timeago|%s months ago'), s__('Timeago|%s months remaining')],
+    () => [s__('Timeago|1 year ago'), s__('Timeago|1 year remaining')],
+    () => [s__('Timeago|%s years ago'), s__('Timeago|%s years remaining')],
+  ];
+
+  return (number, index) => {
+    if (cache[index]) {
+      return cache[index];
+    }
+    cache[index] = timeAgoLocaleRemaining[index] && timeAgoLocaleRemaining[index]();
+    return cache[index];
+  };
+};
+
+const memoizedLocale = () => {
+  const cache = [];
+
+  const timeAgoLocale = [
+    () => [s__('Timeago|just now'), s__('Timeago|right now')],
+    () => [s__('Timeago|just now'), s__('Timeago|in %s seconds')],
+    () => [s__('Timeago|1 minute ago'), s__('Timeago|in 1 minute')],
+    () => [s__('Timeago|%s minutes ago'), s__('Timeago|in %s minutes')],
+    () => [s__('Timeago|1 hour ago'), s__('Timeago|in 1 hour')],
+    () => [s__('Timeago|%s hours ago'), s__('Timeago|in %s hours')],
+    () => [s__('Timeago|1 day ago'), s__('Timeago|in 1 day')],
+    () => [s__('Timeago|%s days ago'), s__('Timeago|in %s days')],
+    () => [s__('Timeago|1 week ago'), s__('Timeago|in 1 week')],
+    () => [s__('Timeago|%s weeks ago'), s__('Timeago|in %s weeks')],
+    () => [s__('Timeago|1 month ago'), s__('Timeago|in 1 month')],
+    () => [s__('Timeago|%s months ago'), s__('Timeago|in %s months')],
+    () => [s__('Timeago|1 year ago'), s__('Timeago|in 1 year')],
+    () => [s__('Timeago|%s years ago'), s__('Timeago|in %s years')],
+  ];
+
+  return (number, index) => {
+    if (cache[index]) {
+      return cache[index];
+    }
+    cache[index] = timeAgoLocale[index] && timeAgoLocale[index]();
+    return cache[index];
+  };
+};
+
+timeago.register(timeagoLanguageCode, memoizedLocale());
+timeago.register(`${timeagoLanguageCode}-remaining`, memoizedLocaleRemaining());
+
+export const getTimeago = () => timeago;
+
+/**
+ * For the given elements, sets a tooltip with a formatted date.
+ * @param {JQuery} $timeagoEls
+ * @param {Boolean} setTimeago
+ */
+export const localTimeAgo = ($timeagoEls, setTimeago = true) => {
+  $timeagoEls.each((i, el) => {
+    $(el).text(timeago.format($(el).attr('datetime'), timeagoLanguageCode));
+  });
+
+  if (!setTimeago) {
+    return;
+  }
+
+  function addTimeAgoTooltip() {
+    $timeagoEls.each((i, el) => {
+      // Recreate with custom template
+      el.setAttribute('title', formatDate(el.dateTime));
+    });
+  }
+
+  requestIdleCallback(addTimeAgoTooltip);
+};
+
+/**
+ * Returns remaining or passed time over the given time.
+ * @param {*} time
+ * @param {*} expiredLabel
+ */
+export const timeFor = (time, expiredLabel) => {
+  if (!time) {
+    return '';
+  }
+  if (new Date(time) < new Date()) {
+    return expiredLabel || s__('Timeago|Past due');
+  }
+  return timeago.format(time, `${timeagoLanguageCode}-remaining`).trim();
+};
+
+window.gl = window.gl || {};
+window.gl.utils = {
+  ...(window.gl.utils || {}),
+  localTimeAgo,
+};