<A, E>(self: FiberHandle<A, E>): Effect.Effect<void>Interrupts the fiber currently stored in the FiberHandle, if any, and
leaves the handle empty.
Example (Clearing a fiber handle)
import { Effect, FiberHandle } from "effect"
Effect.gen(function*() {
const handle = yield* FiberHandle.make()
// Add a fiber
yield* FiberHandle.run(handle, Effect.never)
// Clear the handle, interrupting the fiber
yield* FiberHandle.clear(handle)
// The handle is now empty
const fiber = FiberHandle.getUnsafe(handle)
console.log(fiber) // Option.none()
})combinators
Source effect/FiberHandle.ts:49914 lines
export const const clear: <A, E>(
self: FiberHandle<A, E>
) => Effect.Effect<void>
Interrupts the fiber currently stored in the FiberHandle, if any, and
leaves the handle empty.
Example (Clearing a fiber handle)
import { Effect, FiberHandle } from "effect"
Effect.gen(function*() {
const handle = yield* FiberHandle.make()
// Add a fiber
yield* FiberHandle.run(handle, Effect.never)
// Clear the handle, interrupting the fiber
yield* FiberHandle.clear(handle)
// The handle is now empty
const fiber = FiberHandle.getUnsafe(handle)
console.log(fiber) // Option.none()
})
clear = <function (type parameter) A in <A, E>(self: FiberHandle<A, E>): Effect.Effect<void>A, function (type parameter) E in <A, E>(self: FiberHandle<A, E>): Effect.Effect<void>E>(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>(self: FiberHandle<A, E>): Effect.Effect<void>A, function (type parameter) E in <A, E>(self: FiberHandle<A, E>): Effect.Effect<void>E>): import EffectEffect.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<void> =>
import EffectEffect.const uninterruptibleMask: <A, E, R>(
f: (
restore: <AX, EX, RX>(
effect: Effect<AX, EX, RX>
) => Effect<AX, EX, RX>
) => Effect<A, E, R>
) => Effect<A, E, R>
Disables interruption and provides a restore function to restore the
interruptible state within the effect.
Example (Restoring interruption in protected regions)
import { Console, Effect } from "effect"
const program = Effect.uninterruptibleMask((restore) =>
Effect.gen(function*() {
yield* Console.log("Uninterruptible phase...")
yield* Effect.sleep("1 second")
// Restore interruptibility for this part
yield* restore(
Effect.gen(function*() {
yield* Console.log("Interruptible phase...")
yield* Effect.sleep("2 seconds")
})
)
yield* Console.log("Back to uninterruptible")
})
)
uninterruptibleMask((restore: <AX, EX, RX>(
effect: Effect<AX, EX, RX>
) => Effect<AX, EX, RX>
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" || 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) {
return import EffectEffect.const void: Effect.Effect<void, never, never>(alias) const void: {
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;
}
Returns an effect that succeeds with void.
void
}
return import EffectEffect.const andThen: {
<A, B, E2, R2>(
f: (a: A) => Effect<B, E2, R2>
): <E, R>(
self: Effect<A, E, R>
) => Effect<B, E | E2, R | R2>
<B, E2, R2>(f: Effect<B, E2, R2>): <A, E, R>(
self: Effect<A, E, R>
) => Effect<B, E | E2, R | R2>
<A, E, R, B, E2, R2>(
self: Effect<A, E, R>,
f: (a: A) => Effect<B, E2, R2>
): Effect<B, E | E2, R | R2>
<A, E, R, B, E2, R2>(
self: Effect<A, E, R>,
f: Effect<B, E2, R2>
): Effect<B, E | E2, R | R2>
}
restore: <AX, EX, RX>(
effect: Effect<AX, EX, RX>
) => Effect<AX, EX, RX>
import FiberFiber.const interruptAs: {
(
fiberId: number | undefined,
annotations?:
| Context.Context<never>
| undefined
): <A, E>(self: Fiber<A, E>) => Effect<void>
<A, E>(
self: Fiber<A, E>,
fiberId: number | undefined,
annotations?:
| Context.Context<never>
| undefined
): Effect<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;
}
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; <…;
}
const internalFiberId: -1internalFiberId)),
import EffectEffect.const sync: <A>(
thunk: LazyArg<A>
) => Effect<A>
Creates an Effect that represents a synchronous side-effectful computation.
When to use
Use when you need to wrap a synchronous side-effectful operation that is not
expected to throw.
Details
The provided function is evaluated lazily when the effect runs.
Gotchas
The function must not throw. If it throws, the thrown value is treated as a
defect, not as a typed failure. Use try when throwing is expected.
Example (Capturing synchronous logging in an Effect)
import { Effect } from "effect"
const log = (message: string) =>
Effect.sync(() => {
console.log(message) // side effect
})
// ┌─── Effect<void, never, never>
// ▼
const program = log("Hello, World!")
sync(() => {
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") {
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
}
})
)
})