[API reference](https://evolu.dev/docs/api-reference) › [@evolu/common](https://evolu.dev/docs/api-reference/common) › Time Time representations, durations, and scheduling utilities. Durations follow a pattern that other quantities in Evolu repeat, such as sizes in Bytes.ts: - [Millis](https://evolu.dev/docs/api-reference/common/Time/variables/Millis) is the canonical unit, a validated number of milliseconds. - [DurationLiteral](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteral) is the human-readable form, such as `"1.5s"`, validated at compile time and runtime. - [Duration](https://evolu.dev/docs/api-reference/common/Time/type-aliases/Duration) is what APIs accept: `DurationLiteral | Millis`. - [durationToMillis](https://evolu.dev/docs/api-reference/common/Time/functions/durationToMillis) normalizes a `Duration` to `Millis`. ## Core | Name | Description | | ----------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------- | | [Time](https://evolu.dev/docs/api-reference/common/Time/interfaces/Time) | Time and timer operations. | | [TimeDep](https://evolu.dev/docs/api-reference/common/Time/interfaces/TimeDep) | Dependency wrapper for [Time](https://evolu.dev/docs/api-reference/common/Time/interfaces/Time). | | [TimeoutId](https://evolu.dev/docs/api-reference/common/Time/type-aliases/TimeoutId) | Opaque type for timeout handles. | | [createTime](https://evolu.dev/docs/api-reference/common/Time/functions/createTime) | Creates a [Time](https://evolu.dev/docs/api-reference/common/Time/interfaces/Time) using `Date.now()`, `performance`, and `globalThis.setTimeout`. | ## Millis | Name | Description | | ------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [Millis](https://evolu.dev/docs/api-reference/common/Time/type-aliases/Millis) | Non-negative integer milliseconds used for timestamps and durations. | | [PositiveMillis](https://evolu.dev/docs/api-reference/common/Time/type-aliases/PositiveMillis) | Positive [Millis](https://evolu.dev/docs/api-reference/common/Time/variables/Millis) value. | | [maxMillis](https://evolu.dev/docs/api-reference/common/Time/variables/maxMillis) | Maximum [Millis](https://evolu.dev/docs/api-reference/common/Time/variables/Millis) value. | | [Millis](https://evolu.dev/docs/api-reference/common/Time/variables/Millis) | Non-negative integer milliseconds used for timestamps and durations. | | [minMillis](https://evolu.dev/docs/api-reference/common/Time/variables/minMillis) | Minimum [Millis](https://evolu.dev/docs/api-reference/common/Time/variables/Millis) value. | | [ms120fps](https://evolu.dev/docs/api-reference/common/Time/variables/ms120fps) | Frame budget at 120fps (8ms). | | [ms60fps](https://evolu.dev/docs/api-reference/common/Time/variables/ms60fps) | Frame budget at 60fps (16ms). | | [msLongTask](https://evolu.dev/docs/api-reference/common/Time/variables/msLongTask) | Long task threshold (50ms). | | [PositiveMillis](https://evolu.dev/docs/api-reference/common/Time/variables/PositiveMillis) | Positive [Millis](https://evolu.dev/docs/api-reference/common/Time/variables/Millis) value. | | [formatMillisAsClockTime](https://evolu.dev/docs/api-reference/common/Time/functions/formatMillisAsClockTime) | Formats [Millis](https://evolu.dev/docs/api-reference/common/Time/variables/Millis) as local time in `HH:MM:SS.mmm` format. | | [formatMillisAsDuration](https://evolu.dev/docs/api-reference/common/Time/functions/formatMillisAsDuration) | Formats [Millis](https://evolu.dev/docs/api-reference/common/Time/variables/Millis) as a human-readable duration string. | | [millisToDateIso](https://evolu.dev/docs/api-reference/common/Time/functions/millisToDateIso) | Converts [Millis](https://evolu.dev/docs/api-reference/common/Time/variables/Millis) to [DateIso](https://evolu.dev/docs/api-reference/common/Type/variables/DateIso). | | [saturateMillis](https://evolu.dev/docs/api-reference/common/Time/functions/saturateMillis) | Converts a number to [Millis](https://evolu.dev/docs/api-reference/common/Time/variables/Millis), rounding to the nearest millisecond and saturating overflow at [maxMillis](https://evolu.dev/docs/api-reference/common/Time/variables/maxMillis). | ## Durations | Name | Description | | ----------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [DurationLiteralError](https://evolu.dev/docs/api-reference/common/Time/interfaces/DurationLiteralError) | Error returned when [DurationLiteral](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteral) rejects a value. | | [Duration](https://evolu.dev/docs/api-reference/common/Time/type-aliases/Duration) | [DurationLiteral](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteral) or [Millis](https://evolu.dev/docs/api-reference/common/Time/variables/Millis). | | [DurationLiteral](https://evolu.dev/docs/api-reference/common/Time/type-aliases/DurationLiteral) | Duration literal string, from [DurationLiteralMilliseconds](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteralMilliseconds) to [DurationLiteralYears](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteralYears). | | [DurationLiteralDays](https://evolu.dev/docs/api-reference/common/Time/type-aliases/DurationLiteralDays) | Days duration: `"1d"` to `"6d"` or `"1.1d"` to `"6.9d"`. See [DurationLiteral](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteral). | | [DurationLiteralHours](https://evolu.dev/docs/api-reference/common/Time/type-aliases/DurationLiteralHours) | Hours duration: `"1h"` to `"23h"` or `"1.1h"` to `"23.9h"`. See [DurationLiteral](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteral). | | [DurationLiteralMilliseconds](https://evolu.dev/docs/api-reference/common/Time/type-aliases/DurationLiteralMilliseconds) | Milliseconds duration: `"1ms"` to `"999ms"`. See [DurationLiteral](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteral). | | [DurationLiteralMinutes](https://evolu.dev/docs/api-reference/common/Time/type-aliases/DurationLiteralMinutes) | Minutes duration: `"1m"` to `"59m"` or `"1.1m"` to `"59.9m"`. See [DurationLiteral](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteral). | | [DurationLiteralSeconds](https://evolu.dev/docs/api-reference/common/Time/type-aliases/DurationLiteralSeconds) | Seconds duration: `"1s"` to `"59s"` or `"1.1s"` to `"59.9s"`. See [DurationLiteral](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteral). | | [DurationLiteralWeeks](https://evolu.dev/docs/api-reference/common/Time/type-aliases/DurationLiteralWeeks) | Weeks duration: `"1w"` to `"51w"` or `"1.1w"` to `"51.9w"`. See [DurationLiteral](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteral). | | [DurationLiteralYears](https://evolu.dev/docs/api-reference/common/Time/type-aliases/DurationLiteralYears) | Years duration: `"1y"` to `"99y"` or `"1.1y"` to `"99.9y"`. See [DurationLiteral](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteral). | | [PositiveDuration](https://evolu.dev/docs/api-reference/common/Time/type-aliases/PositiveDuration) | [DurationLiteral](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteral) or [PositiveMillis](https://evolu.dev/docs/api-reference/common/Time/variables/PositiveMillis). | | [DurationLiteral](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteral) | Duration literal Type with compile-time and runtime validation. | | [DurationLiteralDays](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteralDays) | Days duration: `"1d"` to `"6d"` or `"1.1d"` to `"6.9d"`. See [DurationLiteral](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteral). | | [DurationLiteralHours](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteralHours) | Hours duration: `"1h"` to `"23h"` or `"1.1h"` to `"23.9h"`. See [DurationLiteral](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteral). | | [DurationLiteralMilliseconds](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteralMilliseconds) | Milliseconds duration: `"1ms"` to `"999ms"`. See [DurationLiteral](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteral). | | [DurationLiteralMinutes](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteralMinutes) | Minutes duration: `"1m"` to `"59m"` or `"1.1m"` to `"59.9m"`. See [DurationLiteral](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteral). | | [DurationLiteralSeconds](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteralSeconds) | Seconds duration: `"1s"` to `"59s"` or `"1.1s"` to `"59.9s"`. See [DurationLiteral](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteral). | | [DurationLiteralWeeks](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteralWeeks) | Weeks duration: `"1w"` to `"51w"` or `"1.1w"` to `"51.9w"`. See [DurationLiteral](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteral). | | [DurationLiteralYears](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteralYears) | Years duration: `"1y"` to `"99y"` or `"1.1y"` to `"99.9y"`. See [DurationLiteral](https://evolu.dev/docs/api-reference/common/Time/variables/DurationLiteral). | | [durationToMillis](https://evolu.dev/docs/api-reference/common/Time/functions/durationToMillis) | Converts a duration to milliseconds. | ## Performance | Name | Description | | ------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------- | | [PerformanceDuration](https://evolu.dev/docs/api-reference/common/Time/type-aliases/PerformanceDuration) | Elapsed fractional milliseconds measured using [PerformanceTime](https://evolu.dev/docs/api-reference/common/Time/type-aliases/PerformanceTime). | | [PerformanceTime](https://evolu.dev/docs/api-reference/common/Time/type-aliases/PerformanceTime) | High-resolution milliseconds elapsed since [PerformanceTimeOrigin](https://evolu.dev/docs/api-reference/common/Time/type-aliases/PerformanceTimeOrigin). | | [PerformanceTimeOrigin](https://evolu.dev/docs/api-reference/common/Time/type-aliases/PerformanceTimeOrigin) | Unix epoch milliseconds used as the origin for [PerformanceTime](https://evolu.dev/docs/api-reference/common/Time/type-aliases/PerformanceTime). | | [performanceDurationBetween](https://evolu.dev/docs/api-reference/common/Time/functions/performanceDurationBetween) | Returns the elapsed fractional milliseconds between two performance times. | ## Testing | Name | Description | | ------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------- | | [TestTime](https://evolu.dev/docs/api-reference/common/Time/interfaces/TestTime) | Test [Time](https://evolu.dev/docs/api-reference/common/Time/interfaces/Time) with controllable timers. | | [TestTimeDep](https://evolu.dev/docs/api-reference/common/Time/interfaces/TestTimeDep) | Dependency wrapper for [TestTime](https://evolu.dev/docs/api-reference/common/Time/interfaces/TestTime). | | [testCreateTime](https://evolu.dev/docs/api-reference/common/Time/functions/testCreateTime) | Creates a [TestTime](https://evolu.dev/docs/api-reference/common/Time/interfaces/TestTime) with controllable timers for testing. |