<A, E>(self: FiberSet<A, E>): Effect.Effect<void>Interrupts all fibers in the FiberSet and clears the set.
Example (Clearing all fibers)
import { Effect, FiberSet } from "effect"
const program = Effect.gen(function*() {
const set = yield* FiberSet.make()
// Add some fibers
yield* FiberSet.run(set, Effect.never)
yield* FiberSet.run(set, Effect.never)
console.log(yield* FiberSet.size(set)) // 2
// Clear all fibers
yield* FiberSet.clear(set)
console.log(yield* FiberSet.size(set)) // 0
})export const const clear: <A, E>(
self: FiberSet<A, E>
) => Effect.Effect<void>
Interrupts all fibers in the FiberSet and clears the set.
Example (Clearing all fibers)
import { Effect, FiberSet } from "effect"
const program = Effect.gen(function*() {
const set = yield* FiberSet.make()
// Add some fibers
yield* FiberSet.run(set, Effect.never)
yield* FiberSet.run(set, Effect.never)
console.log(yield* FiberSet.size(set)) // 2
// Clear all fibers
yield* FiberSet.clear(set)
console.log(yield* FiberSet.size(set)) // 0
})
clear = <function (type parameter) A in <A, E>(self: FiberSet<A, E>): Effect.Effect<void>A, function (type parameter) E in <A, E>(self: FiberSet<A, E>): Effect.Effect<void>E>(self: FiberSet<A, E>(parameter) self: {
deferred: Deferred.Deferred<void, unknown>;
state: { readonly _tag: "Open"; readonly backing: Set<Fiber.Fiber<A, E>> } | { 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 FiberSet<out A = unknown, out E = unknown>A FiberSet is a collection of fibers that can be managed together.
When the associated Scope is closed, all fibers in the set will be interrupted.
Example (Managing fibers in a set)
import { Effect, FiberSet } from "effect"
const program = Effect.gen(function*() {
const set = yield* FiberSet.make<string, string>()
// Add fibers to the set
yield* FiberSet.run(set, Effect.succeed("hello"))
yield* FiberSet.run(set, Effect.succeed("world"))
// Wait for all fibers to complete
yield* FiberSet.awaitEmpty(set)
})
FiberSet<function (type parameter) A in <A, E>(self: FiberSet<A, E>): Effect.Effect<void>A, function (type parameter) E in <A, E>(self: FiberSet<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 suspend: <A, E, R>(
effect: LazyArg<Effect<A, E, R>>
) => Effect<A, E, R>
Creates an Effect lazily, delaying construction until it is needed.
When to use
Use when you need to defer the evaluation of an effect until it is required.
Details
suspend takes a thunk that represents an effect and delays creating it
until the suspended effect is evaluated. This is useful for optimizing
expensive computations, managing circular dependencies such as recursive
functions, and helping TypeScript unify return types when branches construct
different effects. Any side effects or scoped captures inside the thunk are
re-executed on each invocation.
Example (Lazily evaluating side effects)
import { Effect } from "effect"
let i = 0
const bad = Effect.succeed(i++)
const good = Effect.suspend(() => Effect.succeed(i++))
console.log(Effect.runSync(bad)) // Output: 0
console.log(Effect.runSync(bad)) // Output: 0
console.log(Effect.runSync(good)) // Output: 1
console.log(Effect.runSync(good)) // Output: 2
Example (Suspending recursive Fibonacci evaluation)
import { Effect } from "effect"
const blowsUp = (n: number): Effect.Effect<number> =>
n < 2
? Effect.succeed(1)
: Effect.zipWith(blowsUp(n - 1), blowsUp(n - 2), (a, b) => a + b)
// console.log(Effect.runSync(blowsUp(32)))
// crash: JavaScript heap out of memory
const allGood = (n: number): Effect.Effect<number> =>
n < 2
? Effect.succeed(1)
: Effect.zipWith(
Effect.suspend(() => allGood(n - 1)),
Effect.suspend(() => allGood(n - 2)),
(a, b) => a + b
)
console.log(Effect.runSync(allGood(32)))
// Output: 3524578
Example (Helping TypeScript infer recursive effect types)
import { Effect } from "effect"
// Without suspend, TypeScript may struggle with type inference.
// Inferred type:
// (a: number, b: number) =>
// Effect<never, Error, never> | Effect<number, never, never>
const withoutSuspend = (a: number, b: number) =>
b === 0
? Effect.fail(new Error("Cannot divide by zero"))
: Effect.succeed(a / b)
// Using suspend to unify return types.
// Inferred type:
// (a: number, b: number) => Effect<number, Error, never>
const withSuspend = (a: number, b: number) =>
Effect.suspend(() =>
b === 0
? Effect.fail(new Error("Cannot divide by zero"))
: Effect.succeed(a / b)
)
suspend(() => {
if (self: FiberSet<A, E>(parameter) self: {
deferred: Deferred.Deferred<void, unknown>;
state: { readonly _tag: "Open"; readonly backing: Set<Fiber.Fiber<A, E>> } | { 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;
}
FiberSet<A, E>.state: { readonly _tag: "Open"; readonly backing: Set<Fiber.Fiber<A, E>> } | { readonly _tag: "Closed" }state._tag: "Open" | "Closed"_tag === "Closed") {
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 FiberFiber.const interruptAllAs: {
(fiberId: number): <
A extends Iterable<Fiber<any, any>>
>(
fibers: A
) => Effect<void>
<A extends Iterable<Fiber<any, any>>>(
fibers: A,
fiberId: number
): Effect<void>
}
self: FiberSet<A, E>(parameter) self: {
deferred: Deferred.Deferred<void, unknown>;
state: { readonly _tag: "Open"; readonly backing: Set<Fiber.Fiber<A, E>> } | { 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;
}
FiberSet<A, E>.state: { readonly _tag: "Open"; readonly backing: Set<Fiber.Fiber<A, E>> } | { readonly _tag: "Closed" }state.backing: Set<Fiber.Fiber<A, E>>backing, const internalFiberId: -1internalFiberId)
})