Utilities for dealing with Date objects.

Constants

Constants such as SECOND, MINUTE and HOUR can be found in the constants module.

Day of year

dayOfYear returns the number of the day in the year in the local timezone. dayOfYearUtc does the same but in UTC time.

import { dayOfYear } from "https://deno.land/std@0.223.0/datetime/day_of_year.ts";

dayOfYear(new Date("2019-03-11T03:24:00")); // 70

Difference between dates

difference calculates the difference of the 2 given dates in various units.

import { difference } from "https://deno.land/std@0.223.0/datetime/difference.ts";

const date0 = new Date("2018-05-14");
const date1 = new Date("2020-05-13");

difference(date0, date1);
// {
//   milliseconds: 63072000000,
//   seconds: 63072000,
//   minutes: 1051200,
//   hours: 17520,
//   days: 730,
//   weeks: 104,
//   months: 23,
//   quarters: 7,
//   years: 1
// }

Formatting date strings

format formats a date to a string with the specified format.

import { format } from "https://deno.land/std@0.223.0/datetime/format.ts";

const date = new Date(2019, 0, 20, 16, 34, 23, 123);

format(date, "dd-MM-yyyy"); // "20-01-2019"

format(date, "MM-dd-yyyy HH:mm:ss.SSS"); // "01-20-2019 16:34:23.123"

format(date, "'today:' yyyy-MM-dd"); // "today: 2019-01-20"

Detecting leap years

isLeap returns whether the given year is a leap year. isUtcLeap does the same but in UTC time.

import { isLeap } from "https://deno.land/std@0.223.0/datetime/is_leap.ts";

isLeap(new Date("1970-01-02")); // false

isLeap(1970); // false

isLeap(new Date("1972-01-02")); // true

isLeap(1972); // true

Parsing date strings

parse parses a date string using the specified format string.

import { parse } from "https://deno.land/std@0.223.0/datetime/parse.ts";

parse("20-01-2019", "dd-MM-yyyy"); // 2019-01-19T13:00:00.000Z

parse("01-20-2019 04:34 PM", "MM-dd-yyyy hh:mm a"); // 2019-01-20T05:34:00.000Z

parse("01-20-2019 16:34:23.123", "MM-dd-yyyy HH:mm:ss.SSS"); // 2019-01-20T05:34:23.123Z

Week of year

weekOfYear returns the number of the week in the year in the local timezone.

import { weekOfYear } from "https://deno.land/std@0.223.0/datetime/week_of_year.ts";

weekOfYear(new Date("2020-12-28T03:24:00")); // 53

weekOfYear(new Date("2020-07-10T03:24:00")); // 28