dtfm

Locale-agnostic date formatting utilities

Date formatting

formatDate(new Date(), '{YYYY}-{MM}-{DD} {HH}:{mm}:{ss}');
// = 2022-07-19 12:34:56

List of placeholders

Placeholder	Value
{Y}	Year
{YY}	Year, zero-prefixed when shorter than 2 digits
{YYYY}	Year, zero-prefixed when shorter than 4 digits
{yy}	Year, last 2 digits zero-prefixed when shorter than 2 digits
{YE}	Year of a calendar era (specified by AD/BC or CE/BCE)
{E}	Christian era: AD/BC
{CE}	Common Era: CE/BCE
{M}	Month
{MM}	Month, zero-prefixed when shorter than 2 digits
{MMM}	Month abbreviation
{D}	Day
{DD}	Day, zero-prefixed when shorter than 2 digits
{H}	Hours
{HH}	Hours, zero-prefixed when shorter than 2 digits
{h}	12h-clock hours
{hh}	12h-clock hours, zero-prefixed when shorter than 2 digits
{a}	Day period: AM/PM
{m}	Minutes
{mm}	Minutes, zero-prefixed when shorter than 2 digits
{s}	Seconds
{ss}	Seconds, zero-prefixed when shorter than 2 digits
{ms}	Milliseconds, zero-prefixed when shorter than 3 digits
{tz}	Time zone
{WD}	Week day abbreviation
{iso}	Local time zone ISO date string
{isoDate}	Date (= {YYYY}-{MM}-{DD})
{isoTime}	Time (= {HH}:{mm}:{ss})
{isoTimeMs}	Time with milliseconds

The following unformatted date components are also available as placeholder values: timestamp, year, month, day, hours, hours12 (12h-clock hours), minutes, seconds, milliseconds, weekDay, timezoneOffset, input (the first argument of the formatDate() call).

Using external locale-specific formats

formatDate(new Date(), customLocale.fullDate);
// = þriðjudagur 19. júlí 2022

// custom-locale.js (outside the package)
const customWeekDays = [
    'sunnudagur', 'mánudagur', 'þriðjudagur', 'miðvikudagur',
    'fimmtudagur', 'föstudagur', 'laugardagur',
];
const customMonths = [
    'janúar', 'febrúar', 'mars', 'apríl', 'maí', 'júní',
    'júlí', 'ágúst', 'september', 'október', 'nóvember', 'desember',
];
const customFullDateFormat = {
    template: '{WD} {D}. {MMM} {Y}',
    transform: {
        WD: ({ weekDay }) => customWeekDays[weekDay],
        MMM: ({ month }) => customMonths[month - 1],
    },
};
export const customLocale = {
    fullDate: customFullDateFormat,
};

Dynamic templates

let eraTemplate = ({ E }) => E === 'AD' ? '{E} {YE}' : '{YE} {E}';

formatDate('2022-07-19', eraTemplate);
// = AD 2022

formatDate(-62200000000000, eraTemplate);
// = 3 BC

Durations

formatDuration(123456);
// = 2'03.456"