ISO8601-duration

Node/Js-module for parsing and making sense of ISO8601-durations

The ISO8601 duration format

Durations in ISO8601 comes in two formats:

PnYnMnDTnHnMnS - P<date>T<time>
The n is replaced by the value for each of the date and time elements that follow the n.
Leading zeros are not required
PnW - the week format

Check out the details on Wikipedia

Install

$ npm install iso8601-duration

Usage

Most noteworthy of the interface is the ability to provide a date for toSeconds-calculations.
Why becomes evident when working with durations that span dates as all months are not equally long.
E.g January of 2016 is 744 hours compared to the 696 hours of February 2016.

If a date is not provided for toSeconds the timestamp Date.now() is used as baseline.

Interface

export const toSeconds; // fn = (obj, date?) => number
export const pattern;   // ISO8601 RegExp
export const parse;     // fn = string => obj
export default {
	toSeconds,
	pattern,
	parse
}

Example

Simple usage

import {parse, end, toSeconds, pattern} from 'iso8601-duration';

console.log(parse('P1Y2M4DT20H44M12.67S'));
/* outputs =>
{
	years: 1,
	months: 2,
	days: 4,
	hours: 20,
	minutes: 44,
	seconds: 12.67
}
*/

console.log( toSeconds( parse('PT1H30M10.5S') ) );
// outputs => 5410.5

console.log ( end( parse('P1D') ) );
// outputs => DateObj 2017-10-04T10:14:50.190Z

A more complete usecase / example

import {parse, toSeconds, pattern} from 'iso8601-duration';

// convert iso8601 duration-strings to total seconds from some api
const getWithSensibleDurations = someApiEndpoint => {
	// return promise, like fetch does
	return new Promise(resolve => {
		// fetch text
		fetch(someApiEndpoint)
			.then(res => res.text())
			.then(jsonString => {

				// create new pattern that matches on surrounding double-quotes
				// so we can replace the string with an actual number
				const replacePattern = new RegExp(`\\"${pattern.source}\\"`, 'g');
				jsonString = jsonString.replace(replacePattern, m => {
					return toSeconds(parse(m));
				});
				// resolve original request with sensible durations in object
				resolve( JSON.parse(jsonString) );
		});
	});
}

License

MIT @ https://tolu.mit-license.org/

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