<A extends Effect.Effect<any, any, any>>(options: {
readonly label: string
readonly evaluate: (
this: A,
fiber: Fiber.Fiber<any, any>
) => Effect.Effect<
Effect.Success<A>,
Effect.Error<A>,
Effect.Services<A>
>
}): Effect.Effect<Effect.Success<A>, Effect.Error<A>, Effect.Services<A>>Create a low-level Effect prototype.
When to use
Use when you need to create a custom Effect-like value without extending a class, by providing a label and an evaluate function that receives the current fiber.
Details
When the effect is evaluated, it calls evaluate with the current fiber.
prototypesClass
Source effect/Effectable.ts:3111 lines
export const const Prototype: <
A extends Effect.Effect<any, any, any>
>(options: {
readonly label: string
readonly evaluate: (
this: A,
fiber: Fiber.Fiber<any, any>
) => Effect.Effect<
Effect.Success<A>,
Effect.Error<A>,
Effect.Services<A>
>
}) => Effect.Effect<
Effect.Success<A>,
Effect.Error<A>,
Effect.Services<A>
>
Create a low-level Effect prototype.
When to use
Use when you need to create a custom Effect-like value without extending a
class, by providing a label and an evaluate function that receives the
current fiber.
Details
When the effect is evaluated, it calls evaluate with the current fiber.
Prototype = <function (type parameter) A in <A extends Effect.Effect<any, any, any>>(options: {
readonly label: string;
readonly evaluate: (this: A, fiber: Fiber.Fiber<any, any>) => Effect.Effect<Effect.Success<A>, Effect.Error<A>, Effect.Services<A>>;
}): Effect.Effect<Effect.Success<A>, Effect.Error<A>, Effect.Services<A>>
import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<any, any, any>>(options: {
readonly label: string
readonly evaluate: (
this: A,
fiber: Fiber.Fiber<any, any>
) => Effect.Effect<
Effect.Success<A>,
Effect.Error<A>,
Effect.Services<A>
>
}
label: stringlabel: string
readonly evaluate: (
this: A,
fiber: Fiber.Fiber<any, any>
) => Effect.Effect<
Effect.Success<A>,
Effect.Error<A>,
Effect.Services<A>
>
this: A extends Effect.Effect<any, any, any>this: function (type parameter) A in <A extends Effect.Effect<any, any, any>>(options: {
readonly label: string;
readonly evaluate: (this: A, fiber: Fiber.Fiber<any, any>) => Effect.Effect<Effect.Success<A>, Effect.Error<A>, Effect.Services<A>>;
}): Effect.Effect<Effect.Success<A>, Effect.Error<A>, Effect.Services<A>>
fiber: Fiber.Fiber<any, any>(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<any, any>
) => import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<import EffectEffect.type Effect.Success = /*unresolved*/ anySuccess<function (type parameter) A in <A extends Effect.Effect<any, any, any>>(options: {
readonly label: string;
readonly evaluate: (this: A, fiber: Fiber.Fiber<any, any>) => Effect.Effect<Effect.Success<A>, Effect.Error<A>, Effect.Services<A>>;
}): Effect.Effect<Effect.Success<A>, Effect.Error<A>, Effect.Services<A>>
import EffectEffect.type Effect.Error = /*unresolved*/ anyError<function (type parameter) A in <A extends Effect.Effect<any, any, any>>(options: {
readonly label: string;
readonly evaluate: (this: A, fiber: Fiber.Fiber<any, any>) => Effect.Effect<Effect.Success<A>, Effect.Error<A>, Effect.Services<A>>;
}): Effect.Effect<Effect.Success<A>, Effect.Error<A>, Effect.Services<A>>
import EffectEffect.type Effect.Services = /*unresolved*/ anyServices<function (type parameter) A in <A extends Effect.Effect<any, any, any>>(options: {
readonly label: string;
readonly evaluate: (this: A, fiber: Fiber.Fiber<any, any>) => Effect.Effect<Effect.Success<A>, Effect.Error<A>, Effect.Services<A>>;
}): Effect.Effect<Effect.Success<A>, Effect.Error<A>, Effect.Services<A>>
import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<import EffectEffect.type Effect.Success = /*unresolved*/ anySuccess<function (type parameter) A in <A extends Effect.Effect<any, any, any>>(options: {
readonly label: string;
readonly evaluate: (this: A, fiber: Fiber.Fiber<any, any>) => Effect.Effect<Effect.Success<A>, Effect.Error<A>, Effect.Services<A>>;
}): Effect.Effect<Effect.Success<A>, Effect.Error<A>, Effect.Services<A>>
import EffectEffect.type Effect.Error = /*unresolved*/ anyError<function (type parameter) A in <A extends Effect.Effect<any, any, any>>(options: {
readonly label: string;
readonly evaluate: (this: A, fiber: Fiber.Fiber<any, any>) => Effect.Effect<Effect.Success<A>, Effect.Error<A>, Effect.Services<A>>;
}): Effect.Effect<Effect.Success<A>, Effect.Error<A>, Effect.Services<A>>
import EffectEffect.type Effect.Services = /*unresolved*/ anyServices<function (type parameter) A in <A extends Effect.Effect<any, any, any>>(options: {
readonly label: string;
readonly evaluate: (this: A, fiber: Fiber.Fiber<any, any>) => Effect.Effect<Effect.Success<A>, Effect.Error<A>, Effect.Services<A>>;
}): Effect.Effect<Effect.Success<A>, Effect.Error<A>, Effect.Services<A>>
makePrimitiveProto<Op extends string>(options: { readonly op: Op; readonly [evaluate]?: (fiber: FiberImpl) => Primitive | Effect.Effect<any, any, any> | Yield; readonly [contA]?: (this: Primitive, value: any, fiber: FiberImpl) => Primitive | Effect.Effect<any, any, any> | Yield; readonly [contE]?: (this: Primitive, cause: Cause.Cause<any>, fiber: FiberImpl) => Primitive | Effect.Effect<any, any, any> | Yield; readonly [contAll]?: (this: Primitive, fiber: FiberImpl) => void | ((value: any, fiber: FiberImpl) => void) }): PrimitivemakePrimitiveProto({
op: stringop: options: {
readonly label: string
readonly evaluate: (
this: A,
fiber: Fiber.Fiber<any, any>
) => Effect.Effect<
Effect.Success<A>,
Effect.Error<A>,
Effect.Services<A>
>
}
label: stringlabel,
[const evaluate: "~effect/Effect/evaluate"evaluate]: options: {
readonly label: string
readonly evaluate: (
this: A,
fiber: Fiber.Fiber<any, any>
) => Effect.Effect<
Effect.Success<A>,
Effect.Error<A>,
Effect.Services<A>
>
}
evaluate: (
this: A,
fiber: Fiber.Fiber<any, any>
) => Effect.Effect<
Effect.Success<A>,
Effect.Error<A>,
Effect.Services<A>
>
Referenced by 1 symbols