<A, E, XE extends E, XA extends A>(
fiber: Fiber.Fiber<XA, XE>,
options?: {
readonly onlyIfMissing?: boolean | undefined
readonly propagateInterruption?: boolean | undefined
}
): (self: FiberHandle<A, E>) => void
<A, E, XE extends E, XA extends A>(
self: FiberHandle<A, E>,
fiber: Fiber.Fiber<XA, XE>,
options?: {
readonly onlyIfMissing?: boolean | undefined
readonly propagateInterruption?: boolean | undefined
}
): voidSets the fiber in a FiberHandle. When the fiber completes, it will be removed from the FiberHandle.
If a fiber is already running, it will be interrupted unless options.onlyIfMissing is set.
When to use
Use when an existing forked fiber must be installed synchronously into a handle and immediate interruption of replaced or closed fibers is acceptable.
Example (Setting a fiber unsafely)
import { Effect, Fiber, FiberHandle } from "effect"
Effect.gen(function*() {
const handle = yield* FiberHandle.make()
const fiber = Effect.runFork(Effect.succeed("hello"))
// Set the fiber directly (unsafe)
FiberHandle.setUnsafe(handle, fiber)
// The fiber is now managed by the handle
const result = yield* Fiber.await(fiber)
console.log(result) // "hello"
})combinators
Source effect/FiberHandle.ts:29155 lines
export const const setUnsafe: {
<A, E, XE extends E, XA extends A>(
fiber: Fiber.Fiber<XA, XE>,
options?: {
readonly onlyIfMissing?: boolean | undefined
readonly propagateInterruption?:
| boolean
| undefined
}
): (self: FiberHandle<A, E>) => void
<A, E, XE extends E, XA extends A>(
self: FiberHandle<A, E>,
fiber: Fiber.Fiber<XA, XE>,
options?: {
readonly onlyIfMissing?: boolean | undefined
readonly propagateInterruption?:
| boolean
| undefined
}
): void
}
Sets the fiber in a FiberHandle. When the fiber completes, it will be removed from the FiberHandle.
If a fiber is already running, it will be interrupted unless options.onlyIfMissing is set.
When to use
Use when an existing forked fiber must be installed synchronously into a
handle and immediate interruption of replaced or closed fibers is acceptable.
Example (Setting a fiber unsafely)
import { Effect, Fiber, FiberHandle } from "effect"
Effect.gen(function*() {
const handle = yield* FiberHandle.make()
const fiber = Effect.runFork(Effect.succeed("hello"))
// Set the fiber directly (unsafe)
FiberHandle.setUnsafe(handle, fiber)
// The fiber is now managed by the handle
const result = yield* Fiber.await(fiber)
console.log(result) // "hello"
})
setUnsafe: {
<function (type parameter) A in <A, E, XE extends E, XA extends A>(fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): (self: FiberHandle<A, E>) => void
function (type parameter) E in <A, E, XE extends E, XA extends A>(fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): (self: FiberHandle<A, E>) => void
function (type parameter) XE in <A, E, XE extends E, XA extends A>(fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): (self: FiberHandle<A, E>) => void
function (type parameter) E in <A, E, XE extends E, XA extends A>(fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): (self: FiberHandle<A, E>) => void
function (type parameter) XA in <A, E, XE extends E, XA extends A>(fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): (self: FiberHandle<A, E>) => void
function (type parameter) A in <A, E, XE extends E, XA extends A>(fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): (self: FiberHandle<A, E>) => void
fiber: Fiber.Fiber<XA, XE>(parameter) fiber: {
id: number;
currentOpCount: number;
getRef: <A>(ref: Context.Reference<A>) => A;
context: Context.Context<never>;
setContext: (context: Context.Context<never>) => void;
currentScheduler: Scheduler;
currentDispatcher: SchedulerDispatcher;
currentSpan: AnySpan | undefined;
currentLogLevel: LogLevel;
minimumLogLevel: LogLevel;
currentStackFrame: StackFrame | undefined;
maxOpsBeforeYield: number;
currentPreventYield: boolean;
addObserver: (cb: (exit: Exit<A, E>) => void) => () => void;
interruptUnsafe: (fiberId?: number | undefined, annotations?: Context.Context<never> | undefined) => void;
pollUnsafe: () => Exit<A, E> | undefined;
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; <…;
}
import FiberFiber.interface Fiber<out A, out E = never>A runtime fiber is a lightweight thread that executes Effects. Fibers are
the unit of concurrency in Effect. They provide a way to run multiple
Effects concurrently while maintaining structured concurrency and
cancellation safety.
When to use
Use to observe, join, interrupt, or coordinate work that has already been
forked.
Details
A fiber exposes both safe Effect-based operations, such as
await
,
join
, and
interrupt
, and low-level runtime fields used by
the scheduler and runtime internals.
Gotchas
Prefer the exported functions in this module over calling interruptUnsafe
or pollUnsafe directly. The unsafe methods are immediate runtime hooks and
do not provide the same Effect-based sequencing guarantees.
Example (Awaiting a forked fiber)
import { Effect, Fiber } from "effect"
const program = Effect.gen(function*() {
// Fork an effect to run in a new fiber
const fiber = yield* Effect.forkChild(Effect.succeed(42))
// Wait for the fiber to complete and get its result
const result = yield* Fiber.await(fiber)
console.log(result) // Exit.succeed(42)
return result
})
The Fiber namespace contains utility types and functions for working with fibers.
It provides type-level utilities for fiber operations and variance encoding.
When to use
Use to reference type-level helpers associated with Fiber.
Details
The namespace currently exposes type-level support used by the Fiber
interface. Runtime operations are exported as module-level functions.
Example (Working with fiber types)
import { Effect, Fiber } from "effect"
const program = Effect.gen(function*() {
// Create a fiber
const fiber = yield* Effect.forkChild(Effect.succeed(42))
// Use namespace types for variance
const typedFiber: Fiber.Fiber<number, never> = fiber
// Access fiber properties
console.log(`Fiber ID: ${fiber.id}`)
// Join the fiber
const result = yield* Fiber.join(fiber)
return result // 42
})
Fiber<function (type parameter) XA in <A, E, XE extends E, XA extends A>(fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): (self: FiberHandle<A, E>) => void
function (type parameter) XE in <A, E, XE extends E, XA extends A>(fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): (self: FiberHandle<A, E>) => void
options: | {
readonly onlyIfMissing?: boolean | undefined
readonly propagateInterruption?:
| boolean
| undefined
}
| undefined
onlyIfMissing?: boolean | undefinedonlyIfMissing?: boolean | undefined
readonly propagateInterruption?: boolean | undefinedpropagateInterruption?: boolean | undefined
}
): (self: FiberHandle<A, E>(parameter) self: {
deferred: Deferred.Deferred<void, unknown>;
state: { readonly _tag: "Open"; fiber: Fiber.Fiber<A, E> | undefined } | { readonly _tag: "Closed" };
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;
}
interface FiberHandle<out A = unknown, out E = unknown>Scoped handle that manages at most one fiber, interrupts the current fiber
when the handle's scope closes, and removes managed fibers from the handle
when they complete.
Example (Managing a single fiber)
import { Effect, Fiber, FiberHandle } from "effect"
Effect.gen(function*() {
// Create a FiberHandle that can hold fibers producing strings
const handle = yield* FiberHandle.make<string, never>()
// The handle can store and manage a single fiber
const fiber = yield* FiberHandle.run(handle, Effect.succeed("hello"))
const result = yield* Fiber.await(fiber)
console.log(result) // "hello"
})
FiberHandle<function (type parameter) A in <A, E, XE extends E, XA extends A>(fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): (self: FiberHandle<A, E>) => void
function (type parameter) E in <A, E, XE extends E, XA extends A>(fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): (self: FiberHandle<A, E>) => void
function (type parameter) A in <A, E, XE extends E, XA extends A>(self: FiberHandle<A, E>, fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): void
function (type parameter) E in <A, E, XE extends E, XA extends A>(self: FiberHandle<A, E>, fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): void
function (type parameter) XE in <A, E, XE extends E, XA extends A>(self: FiberHandle<A, E>, fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): void
function (type parameter) E in <A, E, XE extends E, XA extends A>(self: FiberHandle<A, E>, fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): void
function (type parameter) XA in <A, E, XE extends E, XA extends A>(self: FiberHandle<A, E>, fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): void
function (type parameter) A in <A, E, XE extends E, XA extends A>(self: FiberHandle<A, E>, fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): void
self: FiberHandle<A, E>(parameter) self: {
deferred: Deferred.Deferred<void, unknown>;
state: { readonly _tag: "Open"; fiber: Fiber.Fiber<A, E> | undefined } | { readonly _tag: "Closed" };
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;
}
interface FiberHandle<out A = unknown, out E = unknown>Scoped handle that manages at most one fiber, interrupts the current fiber
when the handle's scope closes, and removes managed fibers from the handle
when they complete.
Example (Managing a single fiber)
import { Effect, Fiber, FiberHandle } from "effect"
Effect.gen(function*() {
// Create a FiberHandle that can hold fibers producing strings
const handle = yield* FiberHandle.make<string, never>()
// The handle can store and manage a single fiber
const fiber = yield* FiberHandle.run(handle, Effect.succeed("hello"))
const result = yield* Fiber.await(fiber)
console.log(result) // "hello"
})
FiberHandle<function (type parameter) A in <A, E, XE extends E, XA extends A>(self: FiberHandle<A, E>, fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): void
function (type parameter) E in <A, E, XE extends E, XA extends A>(self: FiberHandle<A, E>, fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): void
fiber: Fiber.Fiber<XA, XE>(parameter) fiber: {
id: number;
currentOpCount: number;
getRef: <A>(ref: Context.Reference<A>) => A;
context: Context.Context<never>;
setContext: (context: Context.Context<never>) => void;
currentScheduler: Scheduler;
currentDispatcher: SchedulerDispatcher;
currentSpan: AnySpan | undefined;
currentLogLevel: LogLevel;
minimumLogLevel: LogLevel;
currentStackFrame: StackFrame | undefined;
maxOpsBeforeYield: number;
currentPreventYield: boolean;
addObserver: (cb: (exit: Exit<A, E>) => void) => () => void;
interruptUnsafe: (fiberId?: number | undefined, annotations?: Context.Context<never> | undefined) => void;
pollUnsafe: () => Exit<A, E> | undefined;
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; <…;
}
import FiberFiber.interface Fiber<out A, out E = never>A runtime fiber is a lightweight thread that executes Effects. Fibers are
the unit of concurrency in Effect. They provide a way to run multiple
Effects concurrently while maintaining structured concurrency and
cancellation safety.
When to use
Use to observe, join, interrupt, or coordinate work that has already been
forked.
Details
A fiber exposes both safe Effect-based operations, such as
await
,
join
, and
interrupt
, and low-level runtime fields used by
the scheduler and runtime internals.
Gotchas
Prefer the exported functions in this module over calling interruptUnsafe
or pollUnsafe directly. The unsafe methods are immediate runtime hooks and
do not provide the same Effect-based sequencing guarantees.
Example (Awaiting a forked fiber)
import { Effect, Fiber } from "effect"
const program = Effect.gen(function*() {
// Fork an effect to run in a new fiber
const fiber = yield* Effect.forkChild(Effect.succeed(42))
// Wait for the fiber to complete and get its result
const result = yield* Fiber.await(fiber)
console.log(result) // Exit.succeed(42)
return result
})
The Fiber namespace contains utility types and functions for working with fibers.
It provides type-level utilities for fiber operations and variance encoding.
When to use
Use to reference type-level helpers associated with Fiber.
Details
The namespace currently exposes type-level support used by the Fiber
interface. Runtime operations are exported as module-level functions.
Example (Working with fiber types)
import { Effect, Fiber } from "effect"
const program = Effect.gen(function*() {
// Create a fiber
const fiber = yield* Effect.forkChild(Effect.succeed(42))
// Use namespace types for variance
const typedFiber: Fiber.Fiber<number, never> = fiber
// Access fiber properties
console.log(`Fiber ID: ${fiber.id}`)
// Join the fiber
const result = yield* Fiber.join(fiber)
return result // 42
})
Fiber<function (type parameter) XA in <A, E, XE extends E, XA extends A>(self: FiberHandle<A, E>, fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): void
function (type parameter) XE in <A, E, XE extends E, XA extends A>(self: FiberHandle<A, E>, fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): void
options: | {
readonly onlyIfMissing?: boolean | undefined
readonly propagateInterruption?:
| boolean
| undefined
}
| undefined
onlyIfMissing?: boolean | undefinedonlyIfMissing?: boolean | undefined
readonly propagateInterruption?: boolean | undefinedpropagateInterruption?: boolean | undefined
}
): void
} = dual<(...args: Array<any>) => any, <A, E, XE extends E, XA extends A>(self: FiberHandle<A, E>, fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}) => void>(isDataFirst: (args: IArguments) => boolean, body: <A, E, XE extends E, XA extends A>(self: FiberHandle<A, E>, fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}) => void): ((...args: Array<any>) => any) & (<A, E, XE extends E, XA extends A>(self: FiberHandle<A, E>, fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}) => void) (+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((args: IArgumentsargs) => const isFiberHandle: (
u: unknown
) => u is FiberHandle
Returns true if a value is a FiberHandle by checking for the
FiberHandle runtime marker.
Example (Checking fiber handles)
import { Effect, FiberHandle } from "effect"
Effect.gen(function*() {
const handle = yield* FiberHandle.make()
console.log(FiberHandle.isFiberHandle(handle)) // true
console.log(FiberHandle.isFiberHandle("not a handle")) // false
})
isFiberHandle(args: IArgumentsargs[0]), <function (type parameter) A in <A, E, XE extends E, XA extends A>(self: FiberHandle<A, E>, fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): void
function (type parameter) E in <A, E, XE extends E, XA extends A>(self: FiberHandle<A, E>, fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): void
function (type parameter) XE in <A, E, XE extends E, XA extends A>(self: FiberHandle<A, E>, fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): void
function (type parameter) E in <A, E, XE extends E, XA extends A>(self: FiberHandle<A, E>, fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): void
function (type parameter) XA in <A, E, XE extends E, XA extends A>(self: FiberHandle<A, E>, fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): void
function (type parameter) A in <A, E, XE extends E, XA extends A>(self: FiberHandle<A, E>, fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): void
self: FiberHandle<A, E>(parameter) self: {
deferred: Deferred.Deferred<void, unknown>;
state: { readonly _tag: "Open"; fiber: Fiber.Fiber<A, E> | undefined } | { readonly _tag: "Closed" };
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;
}
interface FiberHandle<out A = unknown, out E = unknown>Scoped handle that manages at most one fiber, interrupts the current fiber
when the handle's scope closes, and removes managed fibers from the handle
when they complete.
Example (Managing a single fiber)
import { Effect, Fiber, FiberHandle } from "effect"
Effect.gen(function*() {
// Create a FiberHandle that can hold fibers producing strings
const handle = yield* FiberHandle.make<string, never>()
// The handle can store and manage a single fiber
const fiber = yield* FiberHandle.run(handle, Effect.succeed("hello"))
const result = yield* Fiber.await(fiber)
console.log(result) // "hello"
})
FiberHandle<function (type parameter) A in <A, E, XE extends E, XA extends A>(self: FiberHandle<A, E>, fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): void
function (type parameter) E in <A, E, XE extends E, XA extends A>(self: FiberHandle<A, E>, fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): void
fiber: Fiber.Fiber<XA, XE>(parameter) fiber: {
id: number;
currentOpCount: number;
getRef: <A>(ref: Context.Reference<A>) => A;
context: Context.Context<never>;
setContext: (context: Context.Context<never>) => void;
currentScheduler: Scheduler;
currentDispatcher: SchedulerDispatcher;
currentSpan: AnySpan | undefined;
currentLogLevel: LogLevel;
minimumLogLevel: LogLevel;
currentStackFrame: StackFrame | undefined;
maxOpsBeforeYield: number;
currentPreventYield: boolean;
addObserver: (cb: (exit: Exit<A, E>) => void) => () => void;
interruptUnsafe: (fiberId?: number | undefined, annotations?: Context.Context<never> | undefined) => void;
pollUnsafe: () => Exit<A, E> | undefined;
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; <…;
}
import FiberFiber.interface Fiber<out A, out E = never>A runtime fiber is a lightweight thread that executes Effects. Fibers are
the unit of concurrency in Effect. They provide a way to run multiple
Effects concurrently while maintaining structured concurrency and
cancellation safety.
When to use
Use to observe, join, interrupt, or coordinate work that has already been
forked.
Details
A fiber exposes both safe Effect-based operations, such as
await
,
join
, and
interrupt
, and low-level runtime fields used by
the scheduler and runtime internals.
Gotchas
Prefer the exported functions in this module over calling interruptUnsafe
or pollUnsafe directly. The unsafe methods are immediate runtime hooks and
do not provide the same Effect-based sequencing guarantees.
Example (Awaiting a forked fiber)
import { Effect, Fiber } from "effect"
const program = Effect.gen(function*() {
// Fork an effect to run in a new fiber
const fiber = yield* Effect.forkChild(Effect.succeed(42))
// Wait for the fiber to complete and get its result
const result = yield* Fiber.await(fiber)
console.log(result) // Exit.succeed(42)
return result
})
The Fiber namespace contains utility types and functions for working with fibers.
It provides type-level utilities for fiber operations and variance encoding.
When to use
Use to reference type-level helpers associated with Fiber.
Details
The namespace currently exposes type-level support used by the Fiber
interface. Runtime operations are exported as module-level functions.
Example (Working with fiber types)
import { Effect, Fiber } from "effect"
const program = Effect.gen(function*() {
// Create a fiber
const fiber = yield* Effect.forkChild(Effect.succeed(42))
// Use namespace types for variance
const typedFiber: Fiber.Fiber<number, never> = fiber
// Access fiber properties
console.log(`Fiber ID: ${fiber.id}`)
// Join the fiber
const result = yield* Fiber.join(fiber)
return result // 42
})
Fiber<function (type parameter) XA in <A, E, XE extends E, XA extends A>(self: FiberHandle<A, E>, fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): void
function (type parameter) XE in <A, E, XE extends E, XA extends A>(self: FiberHandle<A, E>, fiber: Fiber.Fiber<XA, XE>, options?: {
readonly onlyIfMissing?: boolean | undefined;
readonly propagateInterruption?: boolean | undefined;
}): void
options: | {
readonly onlyIfMissing?: boolean | undefined
readonly propagateInterruption?:
| boolean
| undefined
}
| undefined
onlyIfMissing?: boolean | undefinedonlyIfMissing?: boolean | undefined
readonly propagateInterruption?: boolean | undefinedpropagateInterruption?: boolean | undefined
}
): void => {
if (self: FiberHandle<A, E>(parameter) self: {
deferred: Deferred.Deferred<void, unknown>;
state: { readonly _tag: "Open"; fiber: Fiber.Fiber<A, E> | undefined } | { readonly _tag: "Closed" };
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;
}
FiberHandle<A, E>.state: { readonly _tag: "Open"; fiber: Fiber.Fiber<A, E> | undefined } | { readonly _tag: "Closed" }state._tag: "Open" | "Closed"_tag === "Closed") {
fiber: Fiber.Fiber<XA, XE>(parameter) fiber: {
id: number;
currentOpCount: number;
getRef: <A>(ref: Context.Reference<A>) => A;
context: Context.Context<never>;
setContext: (context: Context.Context<never>) => void;
currentScheduler: Scheduler;
currentDispatcher: SchedulerDispatcher;
currentSpan: AnySpan | undefined;
currentLogLevel: LogLevel;
minimumLogLevel: LogLevel;
currentStackFrame: StackFrame | undefined;
maxOpsBeforeYield: number;
currentPreventYield: boolean;
addObserver: (cb: (exit: Exit<A, E>) => void) => () => void;
interruptUnsafe: (fiberId?: number | undefined, annotations?: Context.Context<never> | undefined) => void;
pollUnsafe: () => Exit<A, E> | undefined;
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; <…;
}
Fiber<XA, XE>.interruptUnsafe: (fiberId?: number | undefined, annotations?: Context.Context<never> | undefined) => voidinterruptUnsafe(const internalFiberId: -1internalFiberId)
return
} else if (self: FiberHandle<A, E>(parameter) self: {
deferred: Deferred.Deferred<void, unknown>;
state: { readonly _tag: "Open"; fiber: Fiber.Fiber<A, E> | undefined } | { readonly _tag: "Closed" };
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;
}
FiberHandle<A, E>.state: { readonly _tag: "Open"; fiber: Fiber.Fiber<A, E> | undefined } | { readonly _tag: "Closed" }state.fiber: Fiber.Fiber<A, E> | undefinedfiber !== var undefinedundefined) {
if (options: | {
readonly onlyIfMissing?: boolean | undefined
readonly propagateInterruption?:
| boolean
| undefined
}
| undefined
onlyIfMissing?: boolean | undefinedonlyIfMissing === true) {
fiber: Fiber.Fiber<XA, XE>(parameter) fiber: {
id: number;
currentOpCount: number;
getRef: <A>(ref: Context.Reference<A>) => A;
context: Context.Context<never>;
setContext: (context: Context.Context<never>) => void;
currentScheduler: Scheduler;
currentDispatcher: SchedulerDispatcher;
currentSpan: AnySpan | undefined;
currentLogLevel: LogLevel;
minimumLogLevel: LogLevel;
currentStackFrame: StackFrame | undefined;
maxOpsBeforeYield: number;
currentPreventYield: boolean;
addObserver: (cb: (exit: Exit<A, E>) => void) => () => void;
interruptUnsafe: (fiberId?: number | undefined, annotations?: Context.Context<never> | undefined) => void;
pollUnsafe: () => Exit<A, E> | undefined;
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; <…;
}
Fiber<XA, XE>.interruptUnsafe: (fiberId?: number | undefined, annotations?: Context.Context<never> | undefined) => voidinterruptUnsafe(const internalFiberId: -1internalFiberId)
return
} else if (self: FiberHandle<A, E>(parameter) self: {
deferred: Deferred.Deferred<void, unknown>;
state: { readonly _tag: "Open"; fiber: Fiber.Fiber<A, E> | undefined } | { readonly _tag: "Closed" };
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;
}
FiberHandle<A, E>.state: { readonly _tag: "Open"; fiber: Fiber.Fiber<A, E> | undefined } | { readonly _tag: "Closed" }state.fiber: Fiber.Fiber<A, E> | undefined(property) fiber: {
id: number;
currentOpCount: number;
getRef: <A>(ref: Context.Reference<A>) => A;
context: Context.Context<never>;
setContext: (context: Context.Context<never>) => void;
currentScheduler: Scheduler;
currentDispatcher: SchedulerDispatcher;
currentSpan: AnySpan | undefined;
currentLogLevel: LogLevel;
minimumLogLevel: LogLevel;
currentStackFrame: StackFrame | undefined;
maxOpsBeforeYield: number;
currentPreventYield: boolean;
addObserver: (cb: (exit: Exit<A, E>) => void) => () => void;
interruptUnsafe: (fiberId?: number | undefined, annotations?: Context.Context<never> | undefined) => void;
pollUnsafe: () => Exit<A, E> | undefined;
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; <…;
}
fiber: Fiber.Fiber<XA, XE>(parameter) fiber: {
id: number;
currentOpCount: number;
getRef: <A>(ref: Context.Reference<A>) => A;
context: Context.Context<never>;
setContext: (context: Context.Context<never>) => void;
currentScheduler: Scheduler;
currentDispatcher: SchedulerDispatcher;
currentSpan: AnySpan | undefined;
currentLogLevel: LogLevel;
minimumLogLevel: LogLevel;
currentStackFrame: StackFrame | undefined;
maxOpsBeforeYield: number;
currentPreventYield: boolean;
addObserver: (cb: (exit: Exit<A, E>) => void) => () => void;
interruptUnsafe: (fiberId?: number | undefined, annotations?: Context.Context<never> | undefined) => void;
pollUnsafe: () => Exit<A, E> | undefined;
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; <…;
}
self: FiberHandle<A, E>(parameter) self: {
deferred: Deferred.Deferred<void, unknown>;
state: { readonly _tag: "Open"; fiber: Fiber.Fiber<A, E> | undefined } | { readonly _tag: "Closed" };
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;
}
FiberHandle<A, E>.state: { readonly _tag: "Open"; fiber: Fiber.Fiber<A, E> | undefined } | { readonly _tag: "Closed" }state.fiber: Fiber.Fiber<A, E> | undefined(property) fiber: {
id: number;
currentOpCount: number;
getRef: <A>(ref: Context.Reference<A>) => A;
context: Context.Context<never>;
setContext: (context: Context.Context<never>) => void;
currentScheduler: Scheduler;
currentDispatcher: SchedulerDispatcher;
currentSpan: AnySpan | undefined;
currentLogLevel: LogLevel;
minimumLogLevel: LogLevel;
currentStackFrame: StackFrame | undefined;
maxOpsBeforeYield: number;
currentPreventYield: boolean;
addObserver: (cb: (exit: Exit<A, E>) => void) => () => void;
interruptUnsafe: (fiberId?: number | undefined, annotations?: Context.Context<never> | undefined) => void;
pollUnsafe: () => Exit<A, E> | undefined;
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; <…;
}
Fiber<A, E>.interruptUnsafe: (fiberId?: number | undefined, annotations?: Context.Context<never> | undefined) => voidinterruptUnsafe(const internalFiberId: -1internalFiberId)
self: FiberHandle<A, E>(parameter) self: {
deferred: Deferred.Deferred<void, unknown>;
state: { readonly _tag: "Open"; fiber: Fiber.Fiber<A, E> | undefined } | { readonly _tag: "Closed" };
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;
}
FiberHandle<A, E>.state: { readonly _tag: "Open"; fiber: Fiber.Fiber<A, E> | undefined } | { readonly _tag: "Closed" }state.fiber: Fiber.Fiber<A, E> | undefinedfiber = var undefinedundefined
}
self: FiberHandle<A, E>(parameter) self: {
deferred: Deferred.Deferred<void, unknown>;
state: { readonly _tag: "Open"; fiber: Fiber.Fiber<A, E> | undefined } | { readonly _tag: "Closed" };
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;
}
FiberHandle<A, E>.state: { readonly _tag: "Open"; fiber: Fiber.Fiber<A, E> | undefined } | { readonly _tag: "Closed" }state.fiber: Fiber.Fiber<A, E> | undefinedfiber = fiber: Fiber.Fiber<XA, XE>(parameter) fiber: {
id: number;
currentOpCount: number;
getRef: <A>(ref: Context.Reference<A>) => A;
context: Context.Context<never>;
setContext: (context: Context.Context<never>) => void;
currentScheduler: Scheduler;
currentDispatcher: SchedulerDispatcher;
currentSpan: AnySpan | undefined;
currentLogLevel: LogLevel;
minimumLogLevel: LogLevel;
currentStackFrame: StackFrame | undefined;
maxOpsBeforeYield: number;
currentPreventYield: boolean;
addObserver: (cb: (exit: Exit<A, E>) => void) => () => void;
interruptUnsafe: (fiberId?: number | undefined, annotations?: Context.Context<never> | undefined) => void;
pollUnsafe: () => Exit<A, E> | undefined;
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; <…;
}
fiber: Fiber.Fiber<XA, XE>(parameter) fiber: {
id: number;
currentOpCount: number;
getRef: <A>(ref: Context.Reference<A>) => A;
context: Context.Context<never>;
setContext: (context: Context.Context<never>) => void;
currentScheduler: Scheduler;
currentDispatcher: SchedulerDispatcher;
currentSpan: AnySpan | undefined;
currentLogLevel: LogLevel;
minimumLogLevel: LogLevel;
currentStackFrame: StackFrame | undefined;
maxOpsBeforeYield: number;
currentPreventYield: boolean;
addObserver: (cb: (exit: Exit<A, E>) => void) => () => void;
interruptUnsafe: (fiberId?: number | undefined, annotations?: Context.Context<never> | undefined) => void;
pollUnsafe: () => Exit<A, E> | undefined;
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; <…;
}
Fiber<XA, XE>.addObserver: (cb: (exit: Exit<A, E>) => void) => () => voidaddObserver((exit: Exit.Exit<XA, XE>exit) => {
if (self: FiberHandle<A, E>(parameter) self: {
deferred: Deferred.Deferred<void, unknown>;
state: { readonly _tag: "Open"; fiber: Fiber.Fiber<A, E> | undefined } | { readonly _tag: "Closed" };
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;
}
FiberHandle<A, E>.state: { readonly _tag: "Open"; fiber: Fiber.Fiber<A, E> | undefined } | { readonly _tag: "Closed" }state._tag: "Open" | "Closed"_tag === "Open" && fiber: Fiber.Fiber<XA, XE>(parameter) fiber: {
id: number;
currentOpCount: number;
getRef: <A>(ref: Context.Reference<A>) => A;
context: Context.Context<never>;
setContext: (context: Context.Context<never>) => void;
currentScheduler: Scheduler;
currentDispatcher: SchedulerDispatcher;
currentSpan: AnySpan | undefined;
currentLogLevel: LogLevel;
minimumLogLevel: LogLevel;
currentStackFrame: StackFrame | undefined;
maxOpsBeforeYield: number;
currentPreventYield: boolean;
addObserver: (cb: (exit: Exit<A, E>) => void) => () => void;
interruptUnsafe: (fiberId?: number | undefined, annotations?: Context.Context<never> | undefined) => void;
pollUnsafe: () => Exit<A, E> | undefined;
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; <…;
}
self: FiberHandle<A, E>(parameter) self: {
deferred: Deferred.Deferred<void, unknown>;
state: { readonly _tag: "Open"; fiber: Fiber.Fiber<A, E> | undefined } | { readonly _tag: "Closed" };
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;
}
FiberHandle<A, E>.state: { readonly _tag: "Open"; fiber: Fiber.Fiber<A, E> | undefined } | { readonly _tag: "Closed" }state.fiber: Fiber.Fiber<A, E> | undefinedfiber) {
self: FiberHandle<A, E>(parameter) self: {
deferred: Deferred.Deferred<void, unknown>;
state: { readonly _tag: "Open"; fiber: Fiber.Fiber<A, E> | undefined } | { readonly _tag: "Closed" };
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;
}
FiberHandle<A, E>.state: { readonly _tag: "Open"; fiber: Fiber.Fiber<A, E> | undefined } | { readonly _tag: "Closed" }state.fiber: Fiber.Fiber<A, E> | undefinedfiber = var undefinedundefined
}
if (
import ExitExit.const isFailure: <A, E>(
self: Exit<A, E>
) => self is Failure<A, E>
Checks whether an Exit is a Failure.
When to use
Use as a type guard to narrow Exit<A, E> to Failure<A, E> and access the
cause property.
Example (Narrowing to failure)
import { Exit } from "effect"
const exit = Exit.fail("error")
if (Exit.isFailure(exit)) {
console.log(exit.cause)
}
isFailure(exit: Exit.Exit<XA, XE>exit) &&
(
options: | {
readonly onlyIfMissing?: boolean | undefined
readonly propagateInterruption?:
| boolean
| undefined
}
| undefined
propagateInterruption?: boolean | undefinedpropagateInterruption === true ?
!const isInternalInterruption: <XE>(
a: Cause.Cause<XE>
) => boolean
exit: Exit.Failure<XA, XE>(parameter) exit: {
_tag: "Failure";
cause: Cause.Cause<E>;
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;
}
Failure<XA, XE>.cause: Cause.Cause<E>(property) Failure<XA, XE>.cause: {
reasons: ReadonlyArray<Reason<E>>;
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 hasInterruptsOnly: <E>(
self: Cause<E>
) => boolean
Returns true if every reason in the cause is an Interrupt (and
there is at least one reason).
When to use
Use when you need to detect failures caused only by interruption.
Example (Checking interrupt-only causes)
import { Cause } from "effect"
console.log(Cause.hasInterruptsOnly(Cause.interrupt(123))) // true
console.log(Cause.hasInterruptsOnly(Cause.fail("error"))) // false
console.log(Cause.hasInterruptsOnly(Cause.empty)) // false
hasInterruptsOnly(exit: Exit.Failure<XA, XE>(parameter) exit: {
_tag: "Failure";
cause: Cause.Cause<E>;
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;
}
Failure<XA, XE>.cause: Cause.Cause<E>(property) Failure<XA, XE>.cause: {
reasons: ReadonlyArray<Reason<E>>;
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 DeferredDeferred.const doneUnsafe: <A, E>(
self: Deferred<A, E>,
effect: Effect<A, E>
) => boolean
Attempts to complete the Deferred synchronously with the specified
completion effect.
When to use
Use to complete a Deferred synchronously in low-level code that already has
the completion effect.
Details
This mutates the Deferred directly and should be reserved for low-level
code; prefer the effectful completion APIs when possible. Returns true if
this call completed the Deferred, or false if it was already completed.
Example (Completing a Deferred unsafely)
import { Deferred, Effect } from "effect"
const deferred = Deferred.makeUnsafe<number>()
const success = Deferred.doneUnsafe(deferred, Effect.succeed(42))
console.log(success) // true
doneUnsafe(self: FiberHandle<A, E>(parameter) self: {
deferred: Deferred.Deferred<void, unknown>;
state: { readonly _tag: "Open"; fiber: Fiber.Fiber<A, E> | undefined } | { readonly _tag: "Closed" };
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;
}
FiberHandle<out A = unknown, out E = unknown>.deferred: Deferred.Deferred<void, unknown>(property) FiberHandle<out A = unknown, out E = unknown>.deferred: {
effect: Effect<A, E>;
resumes: Array<(effect: Effect<A, E>) => void> | undefined;
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; <…;
}
exit: Exit.Failure<XA, XE>(parameter) exit: {
_tag: "Failure";
cause: Cause.Cause<E>;
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;
}
Referenced by 2 symbols