luxon
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Immutable date wrapper
503 lines (451 loc) • 16.5 kB
JavaScript
import DateTime, { friendlyDateTime } from './datetime';
import Duration, { friendlyDuration } from './duration';
import Settings from './settings';
import { InvalidArgumentError, InvalidIntervalError } from './errors';
const INVALID = 'Invalid Interval';
// checks if the start is equal to or before the end
function validateStartEnd(start, end) {
return !!start && !!end && start.isValid && end.isValid && start <= end;
}
/**
* An Interval object represents a half-open interval of time, where each endpoint is a {@link DateTime}. Conceptually, it's a container for those two endpoints, accompanied by methods for creating, parsing, interrogating, comparing, transforming, and formatting them.
*
* Here is a brief overview of the most commonly used methods and getters in Interval:
*
* * **Creation** To create an Interval, use {@link fromDateTimes}, {@link after}, {@link before}, or {@link fromISO}.
* * **Accessors** Use {@link start} and {@link end} to get the start and end.
* * **Interrogation** To analyze the Interval, use {@link count}, {@link length}, {@link hasSame}, {@link contains}, {@link isAfter}, or {@link isBefore}.
* * **Transformation** To create other Intervals out of this one, use {@link set}, {@link splitAt}, {@link splitBy}, {@link divideEqually}, {@link merge}, {@link xor}, {@link union}, {@link intersection}, or {@link difference}.
* * **Comparison** To compare this Interval to another one, use {@link equals}, {@link overlaps}, {@link abutsStart}, {@link abutsEnd}, {@link engulfs}
* * **Output*** To convert the Interval into other representations, see {@link toString}, {@link toISO}, {@link toFormat}, and {@link toDuration}.
*/
export default class Interval {
/**
* @private
*/
constructor(config) {
/**
* @access private
*/
this.s = config.start;
/**
* @access private
*/
this.e = config.end;
/**
* @access private
*/
this.invalid = config.invalidReason || null;
}
/**
* Create an invalid Interval.
* @return {Interval}
*/
static invalid(reason) {
if (!reason) {
throw new InvalidArgumentError('need to specify a reason the DateTime is invalid');
}
if (Settings.throwOnInvalid) {
throw new InvalidIntervalError(reason);
} else {
return new Interval({ invalidReason: reason });
}
}
/**
* Create an Interval from a start DateTime and an end DateTime. Inclusive of the start but not the end.
* @param {DateTime|Date|Object} start
* @param {DateTime|Date|Object} end
* @return {Interval}
*/
static fromDateTimes(start, end) {
const builtStart = friendlyDateTime(start),
builtEnd = friendlyDateTime(end);
return new Interval({
start: builtStart,
end: builtEnd,
invalidReason: validateStartEnd(builtStart, builtEnd) ? null : 'invalid endpoints'
});
}
/**
* Create an Interval from a start DateTime and a Duration to extend to.
* @param {DateTime|Date|Object} start
* @param {Duration|Object|number} duration - the length of the Interval.
* @return {Interval}
*/
static after(start, duration) {
const dur = friendlyDuration(duration),
dt = friendlyDateTime(start);
return Interval.fromDateTimes(dt, dt.plus(dur));
}
/**
* Create an Interval from an end DateTime and a Duration to extend backwards to.
* @param {DateTime|Date|Object} end
* @param {Duration|Object|number} duration - the length of the Interval.
* @return {Interval}
*/
static before(end, duration) {
const dur = friendlyDuration(duration),
dt = friendlyDateTime(end);
return Interval.fromDateTimes(dt.minus(dur), dt);
}
/**
* Create an Interval from an ISO 8601 string
* @param {string} string - the ISO string to parse
* @param {Object} opts - options to pass {@see DateTime.fromISO}
* @return {Interval}
*/
static fromISO(string, opts) {
if (string) {
const [s, e] = string.split(/\//);
if (s && e) {
return Interval.fromDateTimes(DateTime.fromISO(s, opts), DateTime.fromISO(e, opts));
}
}
return Interval.invalid('invalid ISO format');
}
/**
* Returns the start of the Interval
* @type {DateTime}
*/
get start() {
return this.isValid ? this.s : null;
}
/**
* Returns the end of the Interval
* @type {DateTime}
*/
get end() {
return this.isValid ? this.e : null;
}
/**
* Returns whether this Interval's end is at least its start, i.e. that the Interval isn't 'backwards'.
* @type {boolean}
*/
get isValid() {
return this.invalidReason === null;
}
/**
* Returns an explanation of why this Interval became invalid, or null if the Interval is valid
* @type {string}
*/
get invalidReason() {
return this.invalid;
}
/**
* Returns the length of the Interval in the specified unit.
* @param {string} unit - the unit (such as 'hours' or 'days') to return the length in.
* @return {number}
*/
length(unit = 'milliseconds') {
return this.isValid ? this.toDuration(...[unit]).get(unit) : NaN;
}
/**
* Returns the count of minutes, hours, days, months, or years included in the Interval, even in part.
* Unlike {@link length} this counts sections of the calendar, not periods of time, e.g. specifying 'day'
* asks 'what dates are included in this interval?', not 'how many days long is this interval?'
* @param {string} [unit='milliseconds'] - the unit of time to count.
* @return {number}
*/
count(unit = 'milliseconds') {
if (!this.isValid) return NaN;
const start = this.start.startOf(unit),
end = this.end.startOf(unit);
return Math.floor(end.diff(start, unit).get(unit)) + 1;
}
/**
* Returns whether this Interval's start and end are both in the same unit of time
* @param {string} unit - the unit of time to check sameness on
* @return {boolean}
*/
hasSame(unit) {
return this.isValid ? this.e.minus(1).hasSame(this.s, unit) : false;
}
/**
* Return whether this Interval has the same start and end DateTimes.
* @return {boolean}
*/
isEmpty() {
return this.s.valueOf() === this.e.valueOf();
}
/**
* Return whether this Interval's start is after the specified DateTime.
* @param {DateTime} dateTime
* @return {boolean}
*/
isAfter(dateTime) {
if (!this.isValid) return false;
return this.s > dateTime;
}
/**
* Return whether this Interval's end is before the specified DateTime.
* @param {DateTime} dateTime
* @return {boolean}
*/
isBefore(dateTime) {
if (!this.isValid) return false;
return this.e <= dateTime;
}
/**
* Return whether this Interval contains the specified DateTime.
* @param {DateTime} dateTime
* @return {boolean}
*/
contains(dateTime) {
if (!this.isValid) return false;
return this.s <= dateTime && this.e > dateTime;
}
/**
* "Sets" the start and/or end dates. Returns a newly-constructed Interval.
* @param {Object} values - the values to set
* @param {DateTime} values.start - the starting DateTime
* @param {DateTime} values.end - the ending DateTime
* @return {Interval}
*/
set({ start, end } = {}) {
if (!this.isValid) return this;
return Interval.fromDateTimes(start || this.s, end || this.e);
}
/**
* Split this Interval at each of the specified DateTimes
* @param {...[DateTime]} dateTimes - the unit of time to count.
* @return {[Interval]}
*/
splitAt(...dateTimes) {
if (!this.isValid) return [];
const sorted = dateTimes.map(friendlyDateTime).sort(),
results = [];
let { s } = this,
i = 0;
while (s < this.e) {
const added = sorted[i] || this.e,
next = +added > +this.e ? this.e : added;
results.push(Interval.fromDateTimes(s, next));
s = next;
i += 1;
}
return results;
}
/**
* Split this Interval into smaller Intervals, each of the specified length.
* Left over time is grouped into a smaller interval
* @param {Duration|Object|number} duration - The length of each resulting interval.
* @return {[Interval]}
*/
splitBy(duration) {
const dur = friendlyDuration(duration);
if (!this.isValid || !dur.isValid || dur.as("milliseconds") === 0) {
return [];
}
let { s } = this,
added,
next;
const results = [];
while (s < this.e) {
added = s.plus(dur);
next = +added > +this.e ? this.e : added;
results.push(Interval.fromDateTimes(s, next));
s = next;
}
return results;
}
/**
* Split this Interval into the specified number of smaller intervals.
* @param {number} numberOfParts - The number of Intervals to divide the Interval into.
* @return {[Interval]}
*/
divideEqually(numberOfParts) {
if (!this.isValid) return [];
return this.splitBy(this.length() / numberOfParts).slice(0, numberOfParts);
}
/**
* Return whether this Interval overlaps with the specified Interval
* @param {Interval} other
* @return {boolean}
*/
overlaps(other) {
return this.e > other.s && this.s < other.e;
}
/**
* Return whether this Interval's end is adjacent to the specified Interval's start.
* @param {Interval} other
* @return {boolean}
*/
abutsStart(other) {
if (!this.isValid) return false;
return +this.e === +other.s;
}
/**
* Return whether this Interval's start is adjacent to the specified Interval's end.
* @param {Interval} other
* @return {boolean}
*/
abutsEnd(other) {
if (!this.isValid) return false;
return +other.e === +this.s;
}
/**
* Return whether this Interval engulfs the start and end of the specified Interval.
* @param {Interval} other
* @return {boolean}
*/
engulfs(other) {
if (!this.isValid) return false;
return this.s <= other.s && this.e >= other.e;
}
/**
* Return whether this Interval has the same start and end as the specified Interval.
* @param {Interval} other
* @return {boolean}
*/
equals(other) {
if (!this.isValid || !other.isValid) {
return false;
}
return this.s.equals(other.s) && this.e.equals(other.e);
}
/**
* Return an Interval representing the intersection of this Interval and the specified Interval.
* Specifically, the resulting Interval has the maximum start time and the minimum end time of the two Intervals.
* Returns null if the intersection is empty, i.e., the intervals don't intersect.
* @param {Interval} other
* @return {Interval}
*/
intersection(other) {
if (!this.isValid) return this;
const s = this.s > other.s ? this.s : other.s,
e = this.e < other.e ? this.e : other.e;
if (s > e) {
return null;
} else {
return Interval.fromDateTimes(s, e);
}
}
/**
* Return an Interval representing the union of this Interval and the specified Interval.
* Specifically, the resulting Interval has the minimum start time and the maximum end time of the two Intervals.
* @param {Interval} other
* @return {Interval}
*/
union(other) {
if (!this.isValid) return this;
const s = this.s < other.s ? this.s : other.s,
e = this.e > other.e ? this.e : other.e;
return Interval.fromDateTimes(s, e);
}
/**
* Merge an array of Intervals into a equivalent minimal set of Intervals.
* Combines overlapping and adjacent Intervals.
* @param {[Interval]} intervals
* @return {[Interval]}
*/
static merge(intervals) {
const [found, final] = intervals.sort((a, b) => a.s - b.s).reduce(([sofar, current], item) => {
if (!current) {
return [sofar, item];
} else if (current.overlaps(item) || current.abutsStart(item)) {
return [sofar, current.union(item)];
} else {
return [sofar.concat([current]), item];
}
},
[[], null]);
if (final) {
found.push(final);
}
return found;
}
/**
* Return an array of Intervals representing the spans of time that only appear in one of the specified Intervals.
* @param {[Interval]} intervals
* @return {[Interval]}
*/
static xor(intervals) {
let start = null,
currentCount = 0;
const results = [],
ends = intervals.map(i => [{ time: i.s, type: 's' }, { time: i.e, type: 'e' }]),
flattened = Array.prototype.concat(...ends),
arr = flattened.sort((a, b) => a.time - b.time);
for (const i of arr) {
currentCount += i.type === 's' ? 1 : -1;
if (currentCount === 1) {
start = i.time;
} else {
if (start && +start !== +i.time) {
results.push(Interval.fromDateTimes(start, i.time));
}
start = null;
}
}
return Interval.merge(results);
}
/**
* Return an Interval representing the span of time in this Interval that doesn't overlap with any of the specified Intervals.
* @param {...Interval} intervals
* @return {[Interval]}
*/
difference(...intervals) {
return Interval.xor([this].concat(intervals))
.map(i => this.intersection(i))
.filter(i => i && !i.isEmpty());
}
/**
* Returns a string representation of this Interval appropriate for debugging.
* @return {string}
*/
toString() {
if (!this.isValid) return INVALID;
return `[${this.s.toISO()} – ${this.e.toISO()})`;
}
/**
* Returns a string representation of this Interval appropriate for the REPL.
* @return {string}
*/
inspect() {
if (this.isValid) {
return `Interval {\n start: ${this.start.toISO()},\n end: ${this.end.toISO()},\n zone: ${this
.start.zone.name},\n locale: ${this.start.locale} }`;
} else {
return `Interval { Invalid, reason: ${this.invalidReason} }`;
}
}
/**
* Returns an ISO 8601-compliant string representation of this Interval.
* @see https://en.wikipedia.org/wiki/ISO_8601#Time_intervals
* @param {Object} opts - The same options as {@link DateTime.toISO}
* @return {string}
*/
toISO(opts) {
if (!this.isValid) return INVALID;
return `${this.s.toISO(opts)}/${this.e.toISO(opts)}`;
}
/**
* Returns a string representation of this Interval formatted according to the specified format string.
* @param {string} dateFormat - the format string. This string formats the start and end time. See {@link DateTime.toFormat} for details.
* @param {Object} opts - options
* @param {string} [opts.separator = ' – '] - a separator to place between the start and end representations
* @return {string}
*/
toFormat(dateFormat, { separator = ' – ' } = {}) {
if (!this.isValid) return INVALID;
return `${this.s.toFormat(dateFormat)}${separator}${this.e.toFormat(dateFormat)}`;
}
/**
* Return a Duration representing the time spanned by this interval.
* @param {string|string[]} [unit=['milliseconds']] - the unit or units (such as 'hours' or 'days') to include in the duration.
* @param {Object} opts - options that affect the creation of the Duration
* @param {string} [opts.conversionAccuracy='casual'] - the conversion system to use
* @example Interval.fromDateTimes(dt1, dt2).toDuration().toObject() //=> { milliseconds: 88489257 }
* @example Interval.fromDateTimes(dt1, dt2).toDuration('days').toObject() //=> { days: 1.0241812152777778 }
* @example Interval.fromDateTimes(dt1, dt2).toDuration(['hours', 'minutes']).toObject() //=> { hours: 24, minutes: 34.82095 }
* @example Interval.fromDateTimes(dt1, dt2).toDuration(['hours', 'minutes', 'seconds']).toObject() //=> { hours: 24, minutes: 34, seconds: 49.257 }
* @example Interval.fromDateTimes(dt1, dt2).toDuration('seconds').toObject() //=> { seconds: 88489.257 }
* @return {Duration}
*/
toDuration(unit, opts) {
if (!this.isValid) {
return Duration.invalid(this.invalidReason);
}
return this.e.diff(this.s, unit, opts);
}
}