Temporal

JavaScript’s Date object has been a source of frustration for decades. It’s mutable, doesn’t support non-Gregorian calendars well, and handling time zones is notoriously difficult.

The Temporal API is the modern solution, now stable in Deno since v2.7.

#Why Temporal?

As Mat Marquis explains in his post, Date is essentially “broken” for modern web development:

1. Mutability: Calling a method like setHours() on a Date object changes the original object, leading to subtle bugs.
2. Parsing: Date.parse() is notoriously inconsistent across different browsers.
3. Time Zones: Date only supports the user’s local time and UTC.

Temporal solves these problems by being immutable and providing specialized types for different use cases.

#Getting Started

In Deno, Temporal is available globally. You don’t need to import anything.

#Current Date and Time

The Temporal.Now object provides methods to get the current time in various formats:

// Current date (e.g., 2026-04-07)
const today = Temporal.Now.plainDateISO();

// Current date and time (e.g., 2026-04-07T12:14:30)
const now = Temporal.Now.plainDateTimeISO();

// Exact point in time (UTC)
const instant = Temporal.Now.instant();

#Core Types

Temporal introduces several types to represent time more accurately:

#PlainDate

Represents a date with no time or time zone (e.g., a birthday or a calendar event).

const birthday = Temporal.PlainDate.from("1995-12-07");
console.log(birthday.year); // 1995

#PlainTime

Represents a time of day with no date or time zone (e.g., “the store opens at 9:00”).

const openingTime = Temporal.PlainTime.from("09:00:00");

#ZonedDateTime

A complete date and time in a specific time zone. This is what you should use for most “real-world” events.

const meeting = Temporal.ZonedDateTime.from(
  "2026-03-15T14:30[America/New_York]"
);

// Convert to another time zone easily
const inTokyo = meeting.withTimeZone("Asia/Tokyo");