@applicvision/js-toolbox/src/universal/izza-date.js

A collection of tools for modern JavaScript development

export const YEAR = 'year';
export const MONTH = 'month';
export const DAY = 'day';
export const HOUR = 'hour';
export const MINUTE = 'minute';
export const SECOND = 'second';
export const MILLISECOND = 'millisecond';
export const YEARS = YEAR;
export const MONTHS = MONTH;
export const DAYS = DAY;
export const HOURS = HOUR;
export const MINUTES = MINUTE;
export const SECONDS = SECOND;
export const MILLISECONDS = MILLISECOND;

const units = [YEAR, MONTH, DAY, HOUR, MINUTE, SECOND, MILLISECOND]

function unitsFrom(unit) {
	return units.slice(units.indexOf(unit))
}

const timeUnits = unitsFrom(HOUR)

class IzzaDate extends Date {

	static get YEAR() { return YEAR };
	static get MONTH() { return MONTH };
	static get DAY() { return DAY };
	static get YEARS() { return YEAR };
	static get MONTHS() { return MONTH };
	static get DAYS() { return DAY };

	/**
	 * Add to a date by given amount in given unit.
	 * @param {number} amount Amont to add
	 * @param {'year'|'month'|'day'|'hour'|'minute'|'second'|'millisecond'} unit Unit to add to
	 * @param  {...any} otherChanges Other changes, alternating `amount` and `unit`.
	 * @returns {IzzaDate}
	 */
	add(amount, unit, ...otherChanges) {
		if (amount === undefined && unit === undefined) {
			return this;
		}

		return this
			.set(unit, this.get(unit) + amount)
			.add(...otherChanges);
	}
	/**
	 * Set the value of a given unit.
	 * @param {'year'|'month'|'day'|'hour'|'minute'|'second'|'millisecond'} unit Unit to set
	 * @param {number} value The new value
	 */
	set(unit, value) {
		switch (unit) {
			case YEAR: this.setFullYear(value); break;
			case MONTH: this.setMonth(value); break;
			case DAY: this.setDate(value); break;
			case HOUR: this.setHours(value); break
			case MINUTE: this.setMinutes(value); break
			case SECOND: this.setSeconds(value); break
			case MILLISECOND: this.setMilliseconds(value); break
		}
		return this;
	}
	/**
	 * Get the date's value of a specific unit.
	 * @param {'year'|'month'|'day'|'hour'|'minute'|'second'|'millisecond'} unit Unit to get the value for
	 */
	get(unit) {
		switch (unit) {
			case YEAR: return this.getFullYear();
			case MONTH: return this.getMonth();
			case DAY: return this.getDate();
			case HOUR: return this.getHours();
			case MINUTE: return this.getMinutes();
			case SECOND: return this.getSeconds();
			case MILLISECOND: return this.getMilliseconds();
		}
	}
	/**
	 * Subtract from a date by given amounts in given units.
	 * @param  {...any} changes Repeating pattern of `amount` and `unit`.
	 */
	subtract(...changes) {
		return this.add(...changes.map((value, index) => index % 2 ? value : -value));
	}
	/**
	 * Same as `.add`, but creates a copy before manipulating the date.
	 * Example: `date.dateByAdding(1, 'year', 2, 'months')`
	 * @param {...any} changes Repeating pattern of `amount` and `unit`. 
	 */
	dateByAdding(...changes) {
		return this.copy().add(...changes);
	}
	/**
	 * Same as `.set`, but creates a copy before manipulating the date.
	 * @param {'year'|'month'|'day'|'hour'|'minute'|'second'|'millisecond'} unit Unit to set
	 * @param {number} value The new value for the unit
	 */
	dateBySetting(unit, value) {
		return this.copy().set(unit, value);
	}
	/**
	 * Returns a copy of the date.
	 */
	copy() {
		return new IzzaDate(this)
	}
	/**
	 * Same as `.subtract`, but creates a copy before manupulating the date.
	 * Example: `date.dateBySutracting(1, 'year', 2, 'months')`
	 * @param  {...any} changes Repeating patter of `amount` and `unit`.
	 */
	dateBySubtracting(...changes) {
		return this.copy().subtract(...changes);
	}
	/**
	 * Checks if the date is earlier in the day than the `compareDate`.
	 * @param {Date} compareDate The date to compare with
	 */
	isEarlierInTheDay(compareDate) {
		return timeUnits.some(unit => this.get(unit) < compareDate.get(unit))
	}
	/**
	 * Checks if the date is same time of day as the `compareDate`.
	 * @param {Date} compareDate The date to compare with
	 */
	isSameTimeOfDay(compareDate) {
		return timeUnits.every(unit => this.get(unit) == compareDate.get(unit))
	}
	/**
	 * Returns object with values for the given units.
	 * @param {('year'|'month'|'day'|'hour'|'minute'|'second'|'millisecond')[]} [forUnits] the units to get the values for
	 */
	components(forUnits = units) {
		return Object.fromEntries(forUnits.map(unit => [unit, this.get(unit)]))
	}
	/**
	 * Checks if the date is later in the day than the `compareDate`.
	 * @param {Date} compareDate The date to compare with
	 */
	isLaterInTheDay(compareDate) {
		return timeUnits.some(unit => this.get(unit) > compareDate.get(unit))
	}
	/**
	 * Returns the number of days (integer) until `date`. Returns negative number if `date` is in the past.
	 * @param {Date} date Date to get days until
	 * @returns {number}
	 */
	daysUntil(date) {
		const diff = date - this
		return Math.floor(diff / (3600 * 1000 * 24)) + this.isLaterInTheDay(date)
	}
	/**
	 * Returns the number of days (integer) since `date`. Returns negative number if `date` is in the future. 
	 * @param {Date} date Date to get the days since
	 * @returns {number}
	 */
	daysSince(date) {
		return date.daysUntil(this)
	}

}

export default IzzaDate;