piso

ISO 8601 date, duration, and interval parsing package as declared on Wikipedia ISO 8601.

In Spain, piso refers to the whole apartment, whereas in Mexico, it refers only to the floor of your departamento. But the above has nothing to do with this project.

Api

`parseInterval(iso8601Interval[, enforceUTC])`

Parse interval from an ISO 8601 interval string.

iso8601Interval: string with ISO 8601 interval source
enforceUTC: optional boolean, enforce UTC if source lacks time zone offset

Returns ISOInterval.

Interval sources are bounded by their field limits: repetitions accept at most 17 digits, a maximal date — signed 17 digit year, 17 second fractions, and offset with seconds — is 60 characters, and a maximal duration is 129 characters. Consequently a valid interval never exceeds 209 characters.

import { parseInterval, ISOInterval } from '@0dep/piso';

const viableIntervals = [
  '2007-03-01/2007-04-01',
  'P2Y/2007-03-01T13:00:00Z',
  '2007-03-01T13:00:00Z/P2Y',
  'R5/P1Y/2025-05-01T13:00:00Z',
  'R-1/2009-07-01T00:00Z/P1M',
  'R-1/1972-07-01T00:02Z/PT1H3M',
  'R-1/P1M/2024-07-27T00:00Z',
  '2007-318/2007-319',
  '2007-318/319T24:00:00Z',
];

for (const i of viableIntervals) {
  console.log({ [i]: parseInterval(i).getExpireAt(), utc: parseInterval(i, true).getExpireAt() });
}

`parseDuration(iso8601Duration)`

Parse duration from an ISO 8601 duration string.

iso8601Duration: string with ISO 8601 duration source

Returns ISODuration.

Each duration designator value accepts at most 17 digits, so a valid duration never exceeds 129 characters — more throws RangeError.

import { parseDuration } from '@0dep/piso';

const viableDurations = [
  'PT1M5S',
  'PT1M0.5S',
  'PT0.5S',
  'PT0.01S',
  'PT0.001S',
  'PT0.0001S',
  'PT0.5M',
  'PT0.5H',
  'PT1.5H',
  'P0.5D',
  'P1W',
  'P0.5W',
  'P0.5M',
  'P0.5D',
  'P1Y',
  'P1Y2M3W4DT5H6M7S',
  'PT0S',
  'P0D',
];

for (const d of viableDurations) {
  console.log({ [d]: parseDuration(d).getExpireAt() });
}

try {
  // fractions are only allowed on the smallest unit
  parseDuration('P0.5YT3S');
} catch (err) {
  console.log({ err });
}

`getDate(iso8601Date[, enforceUTC])`

Get Date from an ISO 8601 date time string.

iso8601Date: string with ISO 8601 date source, date and number are also accepted
enforceUTC: optional boolean, enforce UTC if source lacks time zone offset

Returns date.

import { getDate } from '@0dep/piso';

const viableDates = [
  '2024-01-27',
  '2024-02-28',
  '2024-02-29',
  '2020-02-29',
  '2016-02-29',
  '2024-W03-2',
  '2024-01',
  '2024-12',
  '20240127',
  '2024-012',
  '2024012',
  '2024-012T08:06:30',
  '2024-02-27T08:06:30',
  '2024-02-27T08:06:30.001',
  '2024-02-27T08:06:30.0011',
  '2024-02-27T08:06:30.0',
  '2024-02-27T08:06:30,001',
  '2024-02-27T08:06:30Z',
  '2024-02-03T08:06:30+02:00',
  '2024-02-03T08:06:30.5+02:00',
  '20240203T080630+0200',
  '2024-02-03T08:06:30-02:30',
  '2024-02-03T08:06:30-02',
  '2025-01-01T12:00:42.01-02:00',
  '2025-01-01T12:00:42.01+02:30',
  '2025-01-01T12:00:42.01+02:30:30',
  '2025-01-01T23:59',
  '2025-01-01T24:00',
  '2025-01-01T24:00:00',
  '2025-01-01T24:00:00.000',
  '2025-01-01T24:00Z',
  '2025-01-01T24:00+01',
  '2025-01-01T24:00:00+01',
  '2025-01-01T24:00:00.00+01',
  '20240127T1200',
  '20240127T120001',
  '20240127T120001,001',
  '2024',
  '+102024',
  '-00000012',
  new Date(2024, 3, 22),
  0,
  Date.UTC(2024, 3, 22),
];

for (const d of viableDates) {
  console.log({ [d]: getDate(d), utc: getDate(d, true) });
}

try {
  getDate('2023-02-29');
} catch (err) {
  console.log({ err });
}

try {
  // not this year
  getDate('2023-W53-1T12:00');
} catch (err) {
  console.log({ err });
}

try {
  // unbalanced separators
  getDate('2023-02-28T1200');
} catch (err) {
  console.log({ err });
}

NB! string without timezone precision is considered local date, or as Wikipedia put it "If no UTC relation information is given with a time representation, the time is assumed to be in local time". Unless, of course, enforce UTC instruction is used.

`getUTCLastWeekOfYear(Y)`

Get last week of year

Y: full year

Returns 52 or 53.

import { getUTCLastWeekOfYear } from '@0dep/piso';

console.log('last week number', getUTCLastWeekOfYear(2024));

`getUTCWeekOneDate(Y)`

Get Monday week one date

Y: full year

Returns date Monday week one

import { getUTCWeekOneDate } from '@0dep/piso';

console.log('Monday week one', getUTCWeekOneDate(2021));

`getISOWeekString([date])`

Get ISO week date string from date.

date: optional date, defaults to now

import { getISOWeekString } from '@0dep/piso';

console.log('date as week', getISOWeekString(new Date(2021, 11, 28)));

`getUTCWeekNumber([date])`

Get weeknumber from date.

date: optional date, defaults to now

Returns:

Y: full year representation of week date
W: week number
weekday:

import { getUTCWeekNumber } from '@0dep/piso';

console.log(getUTCWeekNumber(new Date(2016, 0, 1)));

`new ISOInterval(source[, enforceUTC])`

Interval instance.

Constructor:

source: ISO8601 interval source
enforceUTC: optional boolean, enforce UTC if source lacks time zone offset

Properties:

repeat: number of repeats
start: start date as ISODate
duration: duration as ISODuration
end: end date as ISODate
type: interval type
get startDate: start date as date, requires parse() to be called
get endDate: end date as date, requires parse() to be called

`interval.type`

Number representing the interval type flags. Available after parse.

1: Repeat
2: Start date
4: Duration
8: End date

Example flags

3: Repeat and start date, rather pointless but possible nevertheless
5: Repeat and duration
6: Start date and duration
7: Repeat, start date, and duration
10: Start- and end date
12: Duration and end date
13: Repeat, duration, and end date

Do I have repeat in my interval?

import { parseInterval } from '@0dep/piso';

console.log((parseInterval('R3/P1Y').type & 1) === 1 ? 'Yes' : 'No');
// Yes

console.log((parseInterval('R-1/P1Y').type & 1) === 1 ? 'Yes' : 'No');
// Yes, indefinite number of repetititions

console.log((parseInterval('R-1/2024-03-27/P1Y').type & 1) === 1 ? 'Yes' : 'No');
// Yes, indefinite number of repetititions from start date

console.log((parseInterval('R-1/P1Y/2024-03-27').type & 1) === 1 ? 'Yes' : 'No');
// Yes, indefinite number of repetititions until end date

console.log((parseInterval('R0/P1Y').type & 1) === 1 ? 'Yes' : 'No');
// No, zero is equal to once

console.log((parseInterval('R1/P1Y').type & 1) === 1 ? 'Yes' : 'No');
// No, since it's just once

console.log((parseInterval('R1/2024-03-28').type & 1) === 1 ? 'Yes' : 'No');
// No, pointless repeat

console.log((parseInterval('R1/2024-03-28/31').type & 1) === 1 ? 'Yes' : 'No');
// No, pointless repeat

console.log((parseInterval('R1/P1Y/2024-03-28').type & 1) === 1 ? 'Yes' : 'No');
// No

Is start date defined in my interval?

import { parseInterval } from '@0dep/piso';

const interval = parseInterval('R-1/2024-03-28/P1Y');

console.log((interval.type | 2) === interval.type ? 'Yes' : 'No');

`interval.parse()`

Returns ISOInterval.

Throws RangeError if something is off.

`interval.toJSON()`

Get interval represented as JavaScript Object Notation.

import { ISOInterval } from '@0dep/piso';

console.log(JSON.stringify({ interval: new ISOInterval('R2/P1Y/2024-03-28') }, null, 2));

`new ISODate(source[, options])`

ISO date instance.

Constructor:

source: ISO 8601 date source string
options: optional parsing options
- offset: source string offset column number, -1 is default
- endChars: string with optional characters that mark the end of the ISO date, e.g. /
- enforceSeparators: boolean that will require time part separators such as - and :
- enforceUTC: optional boolean, enforce UTC if source lacks time zone offset

Properties:

result:
- Y: full year
- M: javascript month
- D: date or ordinal day
- H: hours
- m: minutes
- S: seconds
- F: milliseconds, including fractional milliseconds when the source has more than 3 fraction digits; at most 17 fraction digits are accepted, more throws RangeError
- Z: Z, +, −, or -
- OH: offset hours
- Om: offset minutes
- OS: offset seconds
- isValid: boolean indicating if parse was successful

`date.parse()`

`date.parsePartialDate(Y, M, D, W)`

Parse partial date as compared to passed date part arguments.

Y: required full year
M: optional javascript month, required is not ordinal day
D: required date, weekday (1 = Monday .. 7 = Sunday) if W is passed, or ordinal day
W: optional week number, then D is the week day

Returns ISODate

`date.toDate([enforceUTC])`

Get Date represented by source.

enforceUTC: optional boolean, enforce UTC if source lacks time zone offset

`date.toJSON()`

Get Date represented as JavaScript Object Notation.

`new ISODuration(source[, offset])`

Duration instance.

Constructor:

source: duration source string
offset: optional source string offset column number

Properties:

result:
- Y: years
- M: months
- W: weeks
- D: days
- H: hours
- m: minutes
- S: seconds

`duration.toMilliseconds([startDate])`

Get duration in milliseconds from optional start date.

`duration.untilMilliseconds([endDate])`

Get duration in milliseconds until optional end date.

Example

An example to get start and end date:

import { parseInterval } from '@0dep/piso';

const source = '2007-03-01T13:00:00Z/P1Y2M10DT2H30M';

const interval = parseInterval(source);

console.log('starts at', interval.getStartAt());
console.log('expires at', interval.getExpireAt());
console.log('duration milliseconds', interval.duration.toMilliseconds());

An example to get duration milliseconds:

import { parseDuration } from '@0dep/piso';

const duration = parseDuration('PT2H30M');

console.log('duration millisecods', duration.toMilliseconds(new Date()));

Repetitions

With end date

R4/P2Y/2007-08-01

Repetition	start at	expire at
4	1999-08-01	2001-08-01
3	2001-08-01	2003-08-01
2	2003-08-01	2005-08-01
1	2005-08-01	2007-08-01

Benchmarking

How piso stacks up against the RegExp-based implementations depends on the capability, so speed and functionality are compared per capability below.

Benchmarks and functionality comparison against luxon, iso8601-duration, temporal, and native Date live in the bench workspace. npm run bench measures parse throughput and npm run compare executes each capability below against every library and prints ✓/✗ tables from actual behavior:

npm install
npm run bench
npm run compare

Interval

Parses intervals 6–11 times faster than luxon, depending on the interval form.

Capability	piso	luxon
start/end	✓	✓
start/duration	✓	✓
duration/end	✓	✓
Repeating interval	✓	❌
Relative end date	✓	❌*

* 2007-11-13/15 parses but the relative end resolves to a time of day instead of a date

Duration

Parses durations 1.1–2.3 times faster than luxon and iso8601-duration, and 1.9–4.3 times faster than temporal.

Capability	piso	iso8601-duration	luxon	temporal
Fractional time designator	✓	✓	✓	✓
Invalid if more than one fraction	✓	✓	❌	✓
Year designator	✓	✓	✓	❌
Fractional date designator	✓	❌	✓	❌
Comma as fraction separator	✓	✓	❌	✓
Repeated duration instruction	✓	✓*	❌	❌

* parses to the correct duration but the repeat instruction is ignored

Date

Parses dates 6–7 times faster than luxon and 2–4 times faster than temporal. Native new Date('2024-03-26') is, of course, still faster — about 3 times in the benchmark. On the other hand new Date('2024-03-26') resolves to UTC while new Date(2024, 2, 26) does not. Not sure what to expect but IMHO new Date('2024-03-26') should be a local date.

Capability	piso	luxon	temporal	node 20
The 24:th hour	✓	✓	❌	✓
Year +10000	✓	✓	✓	✓
Year 9999	✓	✓	✓	✓
Year only (`YYYY`)	✓	✓	❌	✓
BC dates	✓	✓	✓	✓
Week	✓	✓	❌	❌
Ordinal date	✓	✓	❌	❌
Without separators	✓	✓	✓	❌
Without offset minutes	✓	✓	✓	❌
Comma as fraction separator	✓	✓	✓	❌
Throw on invalid leap year	✓	✓	✓	❌*
Offset unicode minus (−)	✓	❌	❌	❌
Offset seconds	✓	❌	✓	❌
36 fractions of a second	❌**	❌	❌	✓

* node is benevolent when parsing 2100-02-29 as 2100-03-01
** piso accepts at most 17 fraction digits, more throws RangeError

Name		Name	Last commit message	Last commit date
.github/workflows		.github/workflows
bench		bench
src		src
test		test
types		types
.gitignore		.gitignore
.mocharc.json		.mocharc.json
.nvmrc		.nvmrc
.prettierignore		.prettierignore
.prettierrc.json		.prettierrc.json
AGENTS.md		AGENTS.md
CHANGELOG.md		CHANGELOG.md
LICENSE		LICENSE
README.md		README.md
eslint.config.js		eslint.config.js
package.json		package.json
rollup.config.js		rollup.config.js
tsconfig.json		tsconfig.json

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piso

Contents

Api

`parseInterval(iso8601Interval[, enforceUTC])`

`parseDuration(iso8601Duration)`

`getDate(iso8601Date[, enforceUTC])`

`getUTCLastWeekOfYear(Y)`

`getUTCWeekOneDate(Y)`

`getISOWeekString([date])`

`getUTCWeekNumber([date])`

`new ISOInterval(source[, enforceUTC])`

`interval.type`

`interval.parse()`

`interval.toJSON()`

`new ISODate(source[, options])`

`date.parse()`

`date.parsePartialDate(Y, M, D, W)`

`date.toDate([enforceUTC])`

`date.toJSON()`

`new ISODuration(source[, offset])`

`duration.toMilliseconds([startDate])`

`duration.untilMilliseconds([endDate])`

Example

Repetitions

With end date

Benchmarking

Interval

Duration

Date

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piso

Contents

Api

parseInterval(iso8601Interval[, enforceUTC])

parseDuration(iso8601Duration)

getDate(iso8601Date[, enforceUTC])

getUTCLastWeekOfYear(Y)

getUTCWeekOneDate(Y)

getISOWeekString([date])

getUTCWeekNumber([date])

new ISOInterval(source[, enforceUTC])

interval.type

interval.parse()

interval.toJSON()

new ISODate(source[, options])

date.parse()

date.parsePartialDate(Y, M, D, W)

date.toDate([enforceUTC])

date.toJSON()

new ISODuration(source[, offset])

duration.toMilliseconds([startDate])

duration.untilMilliseconds([endDate])

Example

Repetitions

With end date

Benchmarking

Interval

Duration

Date

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`parseInterval(iso8601Interval[, enforceUTC])`

`parseDuration(iso8601Duration)`

`getDate(iso8601Date[, enforceUTC])`

`getUTCLastWeekOfYear(Y)`

`getUTCWeekOneDate(Y)`

`getISOWeekString([date])`

`getUTCWeekNumber([date])`

`new ISOInterval(source[, enforceUTC])`

`interval.type`

`interval.parse()`

`interval.toJSON()`

`new ISODate(source[, options])`

`date.parse()`

`date.parsePartialDate(Y, M, D, W)`

`date.toDate([enforceUTC])`

`date.toJSON()`

`new ISODuration(source[, offset])`

`duration.toMilliseconds([startDate])`

`duration.untilMilliseconds([endDate])`