<Input, Output, Output2, Error2 = never, Env2 = never>(
f: (
metadata: Metadata<Output, Input>
) => Output2 | Effect<Output2, Error2, Env2>
): <Error, Env>(
self: Schedule<Output, Input, Error, Env>
) => Schedule<Output2, Input, Error | Error2, Env | Env2>
<Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(
self: Schedule<Output, Input, Error, Env>,
f: (
metadata: Metadata<Output, Input>
) => Output2 | Effect<Output2, Error2, Env2>
): Schedule<Output2, Input, Error | Error2, Env | Env2>Returns a new Schedule that maps each schedule decision to a new output
using the full schedule metadata.
Details
The callback receives the schedule input, output, selected delay duration,
current attempt, and elapsed timing information. Return either a plain value
or an Effect that produces the new output.
Example (Mapping schedule outputs)
import { Console, Effect, Schedule } from "effect"
// Transform schedule output from number to string
const countSchedule = Schedule.recurs(5).pipe(
Schedule.map(({ output: count }) => Effect.succeed(`Execution #${count + 1}`))
)
// Map schedule delays to human-readable format
const readableDelays = Schedule.exponential("100 millis").pipe(
Schedule.map(({ output: delay }) => Effect.succeed(`Next retry in ${delay}`))
)
// Transform numeric output to structured data
const structuredSchedule = Schedule.spaced("1 second").pipe(
Schedule.map(({ output: recurrence }) => Effect.succeed({
iteration: recurrence + 1,
phase: recurrence < 5 ? "warmup" as const : "steady" as const
}))
)
const program = Effect.gen(function*() {
const results = yield* Effect.repeat(
Effect.succeed("task completed"),
structuredSchedule.pipe(
Schedule.upTo({ times: 8 }),
Schedule.tap(({ output: info }) =>
Console.log(
`${info.phase} phase - iteration ${info.iteration}`
)
)
)
)
yield* Console.log(`Completed iterations`)
})
// Map with effectful transformation
const effectfulMap = Schedule.fixed("2 seconds").pipe(
Schedule.map(({ output: count }) =>
Effect.gen(function*() {
yield* Console.log(`Processing count: ${count}`)
return count * 10
})
)
)
// Use timing metadata in the mapped output
const complexSchedule = Schedule.fibonacci("100 millis").pipe(
Schedule.map(({ output: delay, attempt }) =>
Effect.succeed(`Attempt ${attempt} delay: ${delay}`)
)
)mapping
Source effect/Schedule.ts:153031 lines
export const const map: {
<
Input,
Output,
Output2,
Error2 = never,
Env2 = never
>(
f: (
metadata: Metadata<Output, Input>
) => Output2 | Effect<Output2, Error2, Env2>
): <Error, Env>(
self: Schedule<Output, Input, Error, Env>
) => Schedule<
Output2,
Input,
Error | Error2,
Env | Env2
>
<
Output,
Input,
Error,
Env,
Output2,
Error2 = never,
Env2 = never
>(
self: Schedule<Output, Input, Error, Env>,
f: (
metadata: Metadata<Output, Input>
) => Output2 | Effect<Output2, Error2, Env2>
): Schedule<
Output2,
Input,
Error | Error2,
Env | Env2
>
}
Returns a new Schedule that maps each schedule decision to a new output
using the full schedule metadata.
Details
The callback receives the schedule input, output, selected delay duration,
current attempt, and elapsed timing information. Return either a plain value
or an Effect that produces the new output.
Example (Mapping schedule outputs)
import { Console, Effect, Schedule } from "effect"
// Transform schedule output from number to string
const countSchedule = Schedule.recurs(5).pipe(
Schedule.map(({ output: count }) => Effect.succeed(`Execution #${count + 1}`))
)
// Map schedule delays to human-readable format
const readableDelays = Schedule.exponential("100 millis").pipe(
Schedule.map(({ output: delay }) => Effect.succeed(`Next retry in ${delay}`))
)
// Transform numeric output to structured data
const structuredSchedule = Schedule.spaced("1 second").pipe(
Schedule.map(({ output: recurrence }) => Effect.succeed({
iteration: recurrence + 1,
phase: recurrence < 5 ? "warmup" as const : "steady" as const
}))
)
const program = Effect.gen(function*() {
const results = yield* Effect.repeat(
Effect.succeed("task completed"),
structuredSchedule.pipe(
Schedule.upTo({ times: 8 }),
Schedule.tap(({ output: info }) =>
Console.log(
`${info.phase} phase - iteration ${info.iteration}`
)
)
)
)
yield* Console.log(`Completed iterations`)
})
// Map with effectful transformation
const effectfulMap = Schedule.fixed("2 seconds").pipe(
Schedule.map(({ output: count }) =>
Effect.gen(function*() {
yield* Console.log(`Processing count: ${count}`)
return count * 10
})
)
)
// Use timing metadata in the mapped output
const complexSchedule = Schedule.fibonacci("100 millis").pipe(
Schedule.map(({ output: delay, attempt }) =>
Effect.succeed(`Attempt ${attempt} delay: ${delay}`)
)
)
map: {
<function (type parameter) Input in <Input, Output, Output2, Error2 = never, Env2 = never>(f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): <Error, Env>(self: Schedule<Output, Input, Error, Env>) => Schedule<Output2, Input, Error | Error2, Env | Env2>Input, function (type parameter) Output in <Input, Output, Output2, Error2 = never, Env2 = never>(f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): <Error, Env>(self: Schedule<Output, Input, Error, Env>) => Schedule<Output2, Input, Error | Error2, Env | Env2>Output, function (type parameter) Output2 in <Input, Output, Output2, Error2 = never, Env2 = never>(f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): <Error, Env>(self: Schedule<Output, Input, Error, Env>) => Schedule<Output2, Input, Error | Error2, Env | Env2>Output2, function (type parameter) Error2 in <Input, Output, Output2, Error2 = never, Env2 = never>(f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): <Error, Env>(self: Schedule<Output, Input, Error, Env>) => Schedule<Output2, Input, Error | Error2, Env | Env2>Error2 = never, function (type parameter) Env2 in <Input, Output, Output2, Error2 = never, Env2 = never>(f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): <Error, Env>(self: Schedule<Output, Input, Error, Env>) => Schedule<Output2, Input, Error | Error2, Env | Env2>Env2 = never>(
f: (
metadata: Metadata<Output, Input>
) => Output2 | Effect<Output2, Error2, Env2>
metadata: Metadata<Output, Input>(parameter) metadata: {
output: Output;
duration: Duration.Duration;
input: Input;
attempt: number;
start: number;
now: number;
elapsed: number;
elapsedSincePrevious: number;
}
interface Metadata<Output = unknown, Input = unknown>Extended metadata that includes both input metadata and the output value from the schedule.
Metadata<function (type parameter) Output in <Input, Output, Output2, Error2 = never, Env2 = never>(f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): <Error, Env>(self: Schedule<Output, Input, Error, Env>) => Schedule<Output2, Input, Error | Error2, Env | Env2>Output, function (type parameter) Input in <Input, Output, Output2, Error2 = never, Env2 = never>(f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): <Error, Env>(self: Schedule<Output, Input, Error, Env>) => Schedule<Output2, Input, Error | Error2, Env | Env2>Input>) => function (type parameter) Output2 in <Input, Output, Output2, Error2 = never, Env2 = never>(f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): <Error, Env>(self: Schedule<Output, Input, Error, Env>) => Schedule<Output2, Input, Error | Error2, Env | Env2>Output2 | interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<function (type parameter) Output2 in <Input, Output, Output2, Error2 = never, Env2 = never>(f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): <Error, Env>(self: Schedule<Output, Input, Error, Env>) => Schedule<Output2, Input, Error | Error2, Env | Env2>Output2, function (type parameter) Error2 in <Input, Output, Output2, Error2 = never, Env2 = never>(f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): <Error, Env>(self: Schedule<Output, Input, Error, Env>) => Schedule<Output2, Input, Error | Error2, Env | Env2>Error2, function (type parameter) Env2 in <Input, Output, Output2, Error2 = never, Env2 = never>(f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): <Error, Env>(self: Schedule<Output, Input, Error, Env>) => Schedule<Output2, Input, Error | Error2, Env | Env2>Env2>
): <function (type parameter) Error in <Error, Env>(self: Schedule<Output, Input, Error, Env>): Schedule<Output2, Input, Error | Error2, Env | Env2>Error, function (type parameter) Env in <Error, Env>(self: Schedule<Output, Input, Error, Env>): Schedule<Output2, Input, Error | Error2, Env | Env2>Env>(
self: Schedule<Output, Input, Error, Env>(parameter) self: {
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; <…;
}
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<function (type parameter) Output in <Input, Output, Output2, Error2 = never, Env2 = never>(f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): <Error, Env>(self: Schedule<Output, Input, Error, Env>) => Schedule<Output2, Input, Error | Error2, Env | Env2>Output, function (type parameter) Input in <Input, Output, Output2, Error2 = never, Env2 = never>(f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): <Error, Env>(self: Schedule<Output, Input, Error, Env>) => Schedule<Output2, Input, Error | Error2, Env | Env2>Input, function (type parameter) Error in <Error, Env>(self: Schedule<Output, Input, Error, Env>): Schedule<Output2, Input, Error | Error2, Env | Env2>Error, function (type parameter) Env in <Error, Env>(self: Schedule<Output, Input, Error, Env>): Schedule<Output2, Input, Error | Error2, Env | Env2>Env>
) => 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<function (type parameter) Output2 in <Input, Output, Output2, Error2 = never, Env2 = never>(f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): <Error, Env>(self: Schedule<Output, Input, Error, Env>) => Schedule<Output2, Input, Error | Error2, Env | Env2>Output2, function (type parameter) Input in <Input, Output, Output2, Error2 = never, Env2 = never>(f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): <Error, Env>(self: Schedule<Output, Input, Error, Env>) => Schedule<Output2, Input, Error | Error2, Env | Env2>Input, function (type parameter) Error in <Error, Env>(self: Schedule<Output, Input, Error, Env>): Schedule<Output2, Input, Error | Error2, Env | Env2>Error | function (type parameter) Error2 in <Input, Output, Output2, Error2 = never, Env2 = never>(f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): <Error, Env>(self: Schedule<Output, Input, Error, Env>) => Schedule<Output2, Input, Error | Error2, Env | Env2>Error2, function (type parameter) Env in <Error, Env>(self: Schedule<Output, Input, Error, Env>): Schedule<Output2, Input, Error | Error2, Env | Env2>Env | function (type parameter) Env2 in <Input, Output, Output2, Error2 = never, Env2 = never>(f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): <Error, Env>(self: Schedule<Output, Input, Error, Env>) => Schedule<Output2, Input, Error | Error2, Env | Env2>Env2>
<function (type parameter) Output in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Output, function (type parameter) Input in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Input, function (type parameter) Error in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Error, function (type parameter) Env in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Env, function (type parameter) Output2 in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Output2, function (type parameter) Error2 in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Error2 = never, function (type parameter) Env2 in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Env2 = never>(
self: Schedule<Output, Input, Error, Env>(parameter) self: {
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; <…;
}
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<function (type parameter) Output in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Output, function (type parameter) Input in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Input, function (type parameter) Error in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Error, function (type parameter) Env in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Env>,
f: (
metadata: Metadata<Output, Input>
) => Output2 | Effect<Output2, Error2, Env2>
metadata: Metadata<Output, Input>(parameter) metadata: {
output: Output;
duration: Duration.Duration;
input: Input;
attempt: number;
start: number;
now: number;
elapsed: number;
elapsedSincePrevious: number;
}
interface Metadata<Output = unknown, Input = unknown>Extended metadata that includes both input metadata and the output value from the schedule.
Metadata<function (type parameter) Output in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Output, function (type parameter) Input in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Input>) => function (type parameter) Output2 in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Output2 | interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<function (type parameter) Output2 in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Output2, function (type parameter) Error2 in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Error2, function (type parameter) Env2 in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Env2>
): 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<function (type parameter) Output2 in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Output2, function (type parameter) Input in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Input, function (type parameter) Error in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Error | function (type parameter) Error2 in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Error2, function (type parameter) Env in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Env | function (type parameter) Env2 in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Env2>
} = dual<(...args: Array<any>) => any, <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>) => Schedule<Output2, Input, Error | Error2, Env | Env2>>(arity: 2, body: <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>) => Schedule<Output2, Input, Error | Error2, Env | Env2>): ((...args: Array<any>) => any) & (<Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>) => Schedule<Output2, Input, Error | Error2, Env | Env2>) (+1 overload)Creates a function that can be called in data-first style or data-last
(pipe-friendly) style.
When to use
Use to expose one implementation through both direct and pipe-friendly
call styles.
Details
Pass either the arity of the uncurried function or a predicate that decides
whether the current call is data-first. Arity is the common case. Use a
predicate when optional arguments make arity ambiguous.
Example (Selecting data-first or data-last style by arity)
import { Function, pipe } from "effect"
const sum = Function.dual<
(that: number) => (self: number) => number,
(self: number, that: number) => number
>(2, (self, that) => self + that)
console.log(sum(2, 3)) // 5
console.log(pipe(2, sum(3))) // 5
Example (Defining overloads with call signatures)
import { Function, pipe } from "effect"
const sum: {
(that: number): (self: number) => number
(self: number, that: number): number
} = Function.dual(2, (self: number, that: number): number => self + that)
console.log(sum(2, 3)) // 5
console.log(pipe(2, sum(3))) // 5
Example (Selecting data-first or data-last style with a predicate)
import { Function, pipe } from "effect"
const sum = Function.dual<
(that: number) => (self: number) => number,
(self: number, that: number) => number
>(
(args) => args.length === 2,
(self, that) => self + that
)
console.log(sum(2, 3)) // 5
console.log(pipe(2, sum(3))) // 5
dual(2, <function (type parameter) Output in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Output, function (type parameter) Input in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Input, function (type parameter) Error in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Error, function (type parameter) Env in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Env, function (type parameter) Output2 in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Output2, function (type parameter) Error2 in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Error2 = never, function (type parameter) Env2 in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Env2 = never>(
self: Schedule<Output, Input, Error, Env>(parameter) self: {
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; <…;
}
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<function (type parameter) Output in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Output, function (type parameter) Input in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Input, function (type parameter) Error in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Error, function (type parameter) Env in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Env>,
f: (
metadata: Metadata<Output, Input>
) => Output2 | Effect<Output2, Error2, Env2>
metadata: Metadata<Output, Input>(parameter) metadata: {
output: Output;
duration: Duration.Duration;
input: Input;
attempt: number;
start: number;
now: number;
elapsed: number;
elapsedSincePrevious: number;
}
interface Metadata<Output = unknown, Input = unknown>Extended metadata that includes both input metadata and the output value from the schedule.
Metadata<function (type parameter) Output in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Output, function (type parameter) Input in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Input>) => function (type parameter) Output2 in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Output2 | interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<function (type parameter) Output2 in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Output2, function (type parameter) Error2 in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Error2, function (type parameter) Env2 in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Env2>
): 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<function (type parameter) Output2 in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Output2, function (type parameter) Input in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Input, function (type parameter) Error in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Error | function (type parameter) Error2 in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Error2, function (type parameter) Env in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Env | function (type parameter) Env2 in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Env2> =>
const fromStep: <
Input,
Output,
EnvX,
Error,
ErrorX,
Env
>(
step: Effect<
(
now: number,
input: 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 returns a Pull.
Example (Creating a custom schedule from a step function)
import { Cause, Duration, Effect, Schedule } from "effect"
const schedule = Schedule.fromStep(Effect.sync(() => {
let count = 0
return (_now: number, _input: string) => {
if (count >= 3) {
return Cause.done(count)
}
return Effect.succeed([count++, Duration.millis(100)] as [number, Duration.Duration])
}
}))
fromStep(import effecteffect.const map: {
<A, B>(f: (a: A) => B): <E, R>(
self: Effect.Effect<A, E, R>
) => Effect.Effect<B, E, R>
<A, E, R, B>(
self: Effect.Effect<A, E, R>,
f: (a: A) => B
): Effect.Effect<B, E, R>
}
const toStep: <Output, Input, Error, Env>(
schedule: Schedule<Output, Input, Error, Env>
) => Effect<
(
now: number,
input: Input
) => Pull.Pull<
[Output, Duration.Duration],
Error,
Output,
Env
>,
never,
Env
>
Extracts the step function from a Schedule.
Example (Extracting a schedule step function)
import { Effect, Schedule } from "effect"
// Extract step function from an existing schedule
const schedule = Schedule.exponential("100 millis").pipe(Schedule.upTo({ times: 3 }))
const program = Effect.gen(function*() {
const stepFn = yield* Schedule.toStep(schedule)
// Use the step function directly for custom logic. The timestamp is
// supplied by the caller, so tests can pass a deterministic value.
const now = 0
const result = yield* stepFn(now, "input")
console.log(`Step result: ${result}`)
})
toStep(self: Schedule<Output, Input, Error, Env>(parameter) self: {
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; <…;
}
step: (
now: number,
input: Input
) => Pull.Pull<
[Output, Duration.Duration],
Error,
Output,
Env
>
const meta: <In>(
now: number,
input: In
) => InputMetadata<In>
const metadataFn: () => <In>(
now: number,
input: In
) => InputMetadata<In>
now: numbernow, input: Inputinput) =>
import PullPull.const matchEffect: {
<
A,
E,
L,
AS,
ES,
RS,
AF,
EF,
RF,
AH,
EH,
RH
>(options: {
readonly onSuccess: (
value: A
) => Effect<AS, ES, RS>
readonly onFailure: (
failure: Cause.Cause<E>
) => Effect<AF, EF, RF>
readonly onDone: (
leftover: L
) => Effect<AH, EH, RH>
}): <R>(
self: Pull<A, E, L, R>
) => Effect<
AS | AF | AH,
ES | EF | EH,
R | RS | RF | RH
>
<
A,
E,
L,
R,
AS,
ES,
RS,
AF,
EF,
RF,
AH,
EH,
RH
>(
self: Pull<A, E, L, R>,
options: {
readonly onSuccess: (
value: A
) => Effect<AS, ES, RS>
readonly onFailure: (
failure: Cause.Cause<E>
) => Effect<AF, EF, RF>
readonly onDone: (
leftover: L
) => Effect<AH, EH, RH>
}
): Effect<
AS | AF | AH,
ES | EF | EH,
R | RS | RF | RH
>
}
step: (
now: number,
input: Input
) => Pull.Pull<
[Output, Duration.Duration],
Error,
Output,
Env
>
now: numbernow, input: Inputinput), {
onSuccess: (
value: [Output, Duration.Duration]
) => Effect<
[Output2, Duration.Duration],
Error2,
Env2
>
output: Outputoutput, duration: Duration.Duration(parameter) duration: {
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;
}
const result:
| Output2
| Effect<Output2, Error2, Env2>
f: (
metadata: Metadata<Output, Input>
) => Output2 | Effect<Output2, Error2, Env2>
const meta: <In>(
now: number,
input: In
) => InputMetadata<In>
now: numbernow, input: Inputinput), Metadata<Output, Input>.output: Outputoutput, Metadata<Output = unknown, Input = unknown>.duration: Duration.Duration(property) Metadata<Output = unknown, Input = unknown>.duration: {
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;
}
function isEffect(u: unknown): u is Effect.Effect<any, any, any>isEffect(const result:
| Output2
| Effect<Output2, Error2, Env2>
import effecteffect.const succeed: <A>(
value: A
) => Effect.Effect<A>
const result: Output2result, duration: Duration.Duration(parameter) duration: {
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;
}
function (type parameter) Output2 in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Output2, import DurationDuration.Duration])
return import effecteffect.const map: {
<A, B>(f: (a: A) => B): <E, R>(
self: Effect.Effect<A, E, R>
) => Effect.Effect<B, E, R>
<A, E, R, B>(
self: Effect.Effect<A, E, R>,
f: (a: A) => B
): Effect.Effect<B, E, R>
}
const result: Effect<
Output2,
Error2,
Env2
>
const result: {
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;
}
output: Output2output) => [output: Output2output, duration: Duration.Duration(parameter) duration: {
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;
}
function (type parameter) Output2 in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Output2, import DurationDuration.Duration])
},
onFailure: (
failure: Cause.Cause<Error>
) => Effect<never, Error, never>
import effecteffect.const failCause: <E>(
cause: Cause.Cause<E>
) => Effect.Effect<never, E>
function (type parameter) Error in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Error>,
onDone: (
leftover: Output
) => Effect<
never,
Error2 | Cause.Done<Output2>,
Env2
>
output: Outputoutput) => {
const const result:
| Output2
| Effect<Output2, Error2, Env2>
f: (
metadata: Metadata<Output, Input>
) => Output2 | Effect<Output2, Error2, Env2>
const meta: <In>(
now: number,
input: In
) => InputMetadata<In>
now: numbernow, input: Inputinput), Metadata<Output, Input>.output: Outputoutput, Metadata<Output = unknown, Input = unknown>.duration: Duration.Duration(property) Metadata<Output = unknown, Input = unknown>.duration: {
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;
}
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 })
if (!function isEffect(u: unknown): u is Effect.Effect<any, any, any>isEffect(const result:
| Output2
| Effect<Output2, Error2, Env2>
import CauseCause.const done: <A = void>(
value?: A
) => Effect.Effect<never, Done<A>>
Creates an Effect that fails with a Done error. Shorthand for
Effect.fail(Cause.Done(value)).
When to use
Use when you model stream or queue completion through the error channel.
Example (Failing with Done)
import { Cause, Effect } from "effect"
const program = Cause.done("finished")
Effect.runPromiseExit(program).then((exit) => {
console.log(exit._tag) // "Failure"
})
done(const result: Output2result as function (type parameter) Output2 in <Output, Input, Error, Env, Output2, Error2 = never, Env2 = never>(self: Schedule<Output, Input, Error, Env>, f: (metadata: Metadata<Output, Input>) => Output2 | Effect<Output2, Error2, Env2>): Schedule<Output2, Input, Error | Error2, Env | Env2>Output2)
return import effecteffect.const flatMap: {
<A, B, E2, R2>(
f: (a: A) => Effect.Effect<B, E2, R2>
): <E, R>(
self: Effect.Effect<A, E, R>
) => Effect.Effect<B, E | E2, R | R2>
<A, E, R, B, E2, R2>(
self: Effect.Effect<A, E, R>,
f: (a: A) => Effect.Effect<B, E2, R2>
): Effect.Effect<B, E | E2, R | R2>
}
const result: Effect<
Output2,
Error2,
Env2
>
const result: {
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;
}
import CauseCause.const done: <A = void>(
value?: A
) => Effect.Effect<never, Done<A>>
Creates an Effect that fails with a Done error. Shorthand for
Effect.fail(Cause.Done(value)).
When to use
Use when you model stream or queue completion through the error channel.
Example (Failing with Done)
import { Cause, Effect } from "effect"
const program = Cause.done("finished")
Effect.runPromiseExit(program).then((exit) => {
console.log(exit._tag) // "Failure"
})
done)
}
})
})))Referenced by 2 symbols