(interval: Duration.Input): Schedule<number>Schedule that divides the timeline to interval-long windows, and sleeps
until the nearest window boundary every time it recurs.
Details
For example, Schedule.windowed("10 seconds") would produce a schedule as
follows:
10s 10s 10s 10s
|----------|----------|----------|----------|
|action------|sleep---|act|-sleep|action----|Example (Repeating on aligned windows)
import { Console, Effect, Schedule } from "effect"
// Execute tasks at regular intervals aligned to window boundaries
const windowSchedule = Schedule.windowed("5 seconds")
const program = Effect.gen(function*() {
yield* Effect.repeat(
Effect.gen(function*() {
yield* Console.log("Window task executed")
return "window-task"
}),
windowSchedule.pipe(Schedule.upTo({ times: 4 }))
)
})export const const windowed: (
interval: Duration.Input
) => Schedule<number>
Schedule that divides the timeline to interval-long windows, and sleeps
until the nearest window boundary every time it recurs.
Details
For example, Schedule.windowed("10 seconds") would produce a schedule as
follows:
10s 10s 10s 10s
|----------|----------|----------|----------|
|action------|sleep---|act|-sleep|action----|
Example (Repeating on aligned windows)
import { Console, Effect, Schedule } from "effect"
// Execute tasks at regular intervals aligned to window boundaries
const windowSchedule = Schedule.windowed("5 seconds")
const program = Effect.gen(function*() {
yield* Effect.repeat(
Effect.gen(function*() {
yield* Console.log("Window task executed")
return "window-task"
}),
windowSchedule.pipe(Schedule.upTo({ times: 4 }))
)
})
windowed = (interval: Duration.Inputinterval: import DurationDuration.type Input =
| number
| bigint
| Duration.Duration
| readonly [seconds: number, nanos: number]
| `${number} nano`
| `${number} nanos`
| `${number} micro`
| `${number} micros`
| `${number} milli`
| `${number} millis`
| `${number} second`
| `${number} seconds`
| `${number} minute`
| `${number} minutes`
| `${number} hour`
| `${number} hours`
| `${number} day`
| `${number} days`
| `${number} week`
| `${number} weeks`
| "Infinity"
| "-Infinity"
| Duration.DurationObject
Valid input types that can be converted to a Duration.
When to use
Use when an API should accept any value that Effect can convert into a
Duration, including existing durations, millisecond numbers, nanosecond
bigints, high-resolution tuples, duration strings, infinity strings, or
duration objects.
Details
String inputs accept values like "10 seconds", "500 millis",
"Infinity", and "-Infinity". Finite fractional values that are
normalized to nanoseconds are rounded to the nearest nanosecond, with ties
away from zero.
Input): interface Schedule<out Output, in Input = unknown, out Error = never, out Env = never>A Schedule defines a strategy for repeating or retrying effects based on some policy.
Example (Defining retry and repeat schedules)
import { Console, Data, Effect, Schedule } from "effect"
class NetworkError extends Data.TaggedError("NetworkError")<{
readonly attempt: number
}> {}
// Basic retry schedule - retry up to 3 times with exponential backoff
const retrySchedule = Schedule.max([
Schedule.exponential("100 millis"),
Schedule.recurs(3)
])
// Basic repeat schedule - repeat every 30 seconds forever
const repeatSchedule: Schedule.Schedule<number, unknown, never> = Schedule
.spaced("30 seconds")
const program = Effect.gen(function*() {
let attempts = 0
const result1 = yield* Effect.retry(
Effect.gen(function*() {
attempts++
if (attempts < 3) {
return yield* Effect.fail(new NetworkError({ attempt: attempts }))
}
return "Success"
}),
retrySchedule
)
console.log(result1) // "Success"
yield* Console.log("heartbeat").pipe(
Effect.repeat(repeatSchedule.pipe(Schedule.upTo({ times: 5 })))
)
})
The Schedule namespace contains types and utilities for working with schedules.
Schedule<number> => {
const const window: numberwindow = import DurationDuration.const toMillis: (self: Input) => numberConverts a Duration to milliseconds.
Example (Converting durations to milliseconds)
import { Duration } from "effect"
console.log(Duration.toMillis(Duration.seconds(5))) // 5000
console.log(Duration.toMillis(Duration.minutes(2))) // 120000
toMillis(import DurationDuration.const fromInputUnsafe: (
input: Input
) => Duration
Decodes a Duration.Input into a Duration.
When to use
Use when the input has already been validated or comes from a trusted source
and throwing is acceptable for invalid duration syntax.
Gotchas
If the input is not a valid Duration.Input, it throws an error.
Example (Decoding duration inputs)
import { Duration } from "effect"
const duration1 = Duration.fromInputUnsafe(1000) // 1000 milliseconds
const duration2 = Duration.fromInputUnsafe("5 seconds")
const duration3 = Duration.fromInputUnsafe("Infinity")
const duration4 = Duration.fromInputUnsafe([2, 500_000_000]) // 2 seconds and 500ms
fromInputUnsafe(interval: Duration.Inputinterval))
return const fromStepWithMetadata: <
Input,
Output,
EnvX,
ErrorX,
Error,
Env
>(
step: Effect<
(
options: InputMetadata<Input>
) => Pull.Pull<
[Output, Duration.Duration],
ErrorX,
Output,
EnvX
>,
Error,
Env
>
) => Schedule<
Output,
Input,
Error | Pull.ExcludeDone<ErrorX>,
Env | EnvX
>
Creates a Schedule from a step function that receives metadata about the schedule's execution.
Example (Creating a metadata-aware schedule)
import { Cause, Duration, Effect, Schedule } from "effect"
const firstThreeInputs = Schedule.fromStepWithMetadata(Effect.succeed((metadata: Schedule.InputMetadata<string>) => {
if (metadata.attempt > 3) {
return Cause.done("finished")
}
return Effect.succeed([
`attempt ${metadata.attempt}: ${metadata.input}`,
Duration.millis(250)
] as [string, Duration.Duration])
}))
fromStepWithMetadata(import effecteffect.const succeed: <A>(
value: A
) => Effect.Effect<A>
meta: InputMetadata<unknown>(parameter) meta: {
input: Input;
attempt: number;
start: number;
now: number;
elapsed: number;
elapsedSincePrevious: number;
}
import effecteffect.const sync: <A>(
thunk: LazyArg<A>
) => Effect.Effect<A>
meta: InputMetadata<unknown>(parameter) meta: {
input: Input;
attempt: number;
start: number;
now: number;
elapsed: number;
elapsedSincePrevious: number;
}
InputMetadata<Input>.attempt: numberattempt - 1,
const window: numberwindow === 0 ? import DurationDuration.const zero: Durationconst zero: {
value: DurationValue;
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
toString: () => string;
toJSON: () => unknown;
}
A Duration representing zero time.
Example (Referencing the zero duration)
import { Duration } from "effect"
console.log(Duration.toMillis(Duration.zero)) // 0
zero : import DurationDuration.const millis: (millis: number) => DurationCreates a Duration from milliseconds.
Example (Creating durations from milliseconds)
import { Duration } from "effect"
const duration = Duration.millis(1000)
console.log(Duration.toMillis(duration)) // 1000
millis(const window: numberwindow - (meta: InputMetadata<unknown>(parameter) meta: {
input: Input;
attempt: number;
start: number;
now: number;
elapsed: number;
elapsedSincePrevious: number;
}
InputMetadata<Input>.elapsed: numberelapsed % const window: numberwindow))
])
))
}