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zena:time

zena
import {…} from 'zena:time';

Monotonic time measurement, durations, and timers.

Provides Instant for points in time, Duration for spans of time, monotonic() for reading the system monotonic clock, and sleep(duration) for asynchronous waiting.

Examples ​

zena
import { monotonic, sleep, milliseconds } from 'zena:time';

let start = monotonic();
await sleep(milliseconds(50));
let elapsed = monotonic() - start;

Classes

Instant

zena
final extension class Instant
Re-exported from zena:time/types.zena

A point on the monotonic clock: nanoseconds from an arbitrary origin, so only the distance between two instants is meaningful.

Methods
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minus(d: Duration): Instant
#

The instant d before this one. Named because - already means instant minus instant, and one operator gets one method.

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isBefore(other: Instant): boolean
#

True when this instant precedes other.

Operators
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operator -(other: Instant): Duration
#

The span from other to this instant — negative when this instant is the earlier one.

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operator +(d: Duration): Instant
#

The instant d after this one — before it, for a negative d.

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operator ==(other: Instant): boolean
#

Duration

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final extension class Duration
Re-exported from zena:time/types.zena

A signed span of time, in nanoseconds.

Methods
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isPositive(): boolean
#

True for a span longer than zero.

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isNegative(): boolean
#

True for a span shorter than zero.

Operators
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operator +(other: Duration): Duration
#
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operator -(other: Duration): Duration
#
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operator *(k: i64): Duration
#

This span scaled k times.

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operator ==(other: Duration): boolean
#

Functions

sleep

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function sleep(d: Duration): Future<void>

A future that completes after at least d.

"At least": the deadline is when the timer becomes eligible, and it completes through the microtask queue like every other future, so a busy queue can delay it further. A zero-length sleep still yields — it never completes synchronously, per the always-async rule.

monotonic

zena
function monotonic(): Instant

The monotonic clock's reading.

formatTimestamp

zena
function formatTimestamp(epochNanos: i64): String
Re-exported from zena:time/types.zena

The UTC time epochNanos nanoseconds after the Unix epoch, as an ISO 8601 / RFC 3339 timestamp with milliseconds: 2026-10-23T17:04:05.123Z. It counts days the proleptic Gregorian way, with no leap seconds, as Unix time does. Times before the epoch are not supported.

milliseconds

zena
function milliseconds(ms: i64): Duration
Re-exported from zena:time/types.zena

ms milliseconds as a Duration.

nanoseconds

zena
function nanoseconds(ns: i64): Duration
Re-exported from zena:time/types.zena

ns nanoseconds as a Duration.