<A, E>(self: TxEnqueue<A, E>): Effect.Effect<Array<A>, ExcludeDone<E>>Removes and returns all currently buffered elements without changing the queue state.
Details
If the queue is already done with a Cause.Done error, returns an empty array. If the queue is done for any other cause, including interruption or failure, that cause is propagated.
Example (Clearing queues)
import { Effect, TxQueue } from "effect"
const program = Effect.gen(function*() {
const queue = yield* TxQueue.bounded<number>(10)
yield* TxQueue.offerAll(queue, [1, 2, 3, 4, 5])
const sizeBefore = yield* TxQueue.size(queue)
console.log(sizeBefore) // 5
const cleared = yield* TxQueue.clear(queue)
console.log(cleared) // [1, 2, 3, 4, 5]
const sizeAfter = yield* TxQueue.size(queue)
console.log(sizeAfter) // 0
})export const const clear: <A, E>(
self: TxEnqueue<A, E>
) => Effect.Effect<Array<A>, ExcludeDone<E>>
Removes and returns all currently buffered elements without changing the
queue state.
Details
If the queue is already done with a Cause.Done error, returns an empty array. If the queue is done for any other cause, including interruption or failure, that cause is propagated.
Example (Clearing queues)
import { Effect, TxQueue } from "effect"
const program = Effect.gen(function*() {
const queue = yield* TxQueue.bounded<number>(10)
yield* TxQueue.offerAll(queue, [1, 2, 3, 4, 5])
const sizeBefore = yield* TxQueue.size(queue)
console.log(sizeBefore) // 5
const cleared = yield* TxQueue.clear(queue)
console.log(cleared) // [1, 2, 3, 4, 5]
const sizeAfter = yield* TxQueue.size(queue)
console.log(sizeAfter) // 0
})
clear = <function (type parameter) A in <A, E>(self: TxEnqueue<A, E>): Effect.Effect<Array<A>, ExcludeDone<E>>A, function (type parameter) E in <A, E>(self: TxEnqueue<A, E>): Effect.Effect<Array<A>, ExcludeDone<E>>E>(self: TxEnqueue<A, E>(parameter) self: {
strategy: "bounded" | "unbounded" | "dropping" | "sliding";
capacity: number;
items: TxChunk.TxChunk<any>;
stateRef: TxRef.TxRef<State<any, any>>;
toString: () => string;
toJSON: () => unknown;
}
interface TxEnqueue<in A, in E = never>Namespace containing type definitions for TxEnqueue variance annotations.
A TxEnqueue represents the write-only interface of a transactional queue, providing
operations for adding elements (enqueue operations) and inspecting queue state.
Example (Offering values through enqueue handles)
import { Effect, TxQueue } from "effect"
import type { Cause } from "effect"
const program = Effect.gen(function*() {
// Queue without error channel
const queue = yield* TxQueue.bounded<number>(10)
const accepted = yield* TxQueue.offer(queue, 42)
// Queue with error channel for completion signaling
const faultTolerantQueue = yield* TxQueue.bounded<number, string>(10)
yield* TxQueue.offerAll(faultTolerantQueue, [1, 2, 3])
yield* TxQueue.fail(faultTolerantQueue, "processing complete")
// Works with Done for clean completion
const completableQueue = yield* TxQueue.bounded<
string,
Cause.Done
>(5)
yield* TxQueue.offer(completableQueue, "task")
yield* TxQueue.end(completableQueue)
})
TxEnqueue<function (type parameter) A in <A, E>(self: TxEnqueue<A, E>): Effect.Effect<Array<A>, ExcludeDone<E>>A, function (type parameter) E in <A, E>(self: TxEnqueue<A, E>): Effect.Effect<Array<A>, ExcludeDone<E>>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<interface Array<T>Array<function (type parameter) A in <A, E>(self: TxEnqueue<A, E>): Effect.Effect<Array<A>, ExcludeDone<E>>A>, type ExcludeDone<E> = E extends Cause.Done<any> ? never : EExcludes Cause.Done completion signals from an error type union.
When to use
Use to describe the ordinary error type that remains after Cause.Done
completion signals have been handled or filtered out of an error union.
ExcludeDone<function (type parameter) E in <A, E>(self: TxEnqueue<A, E>): Effect.Effect<Array<A>, ExcludeDone<E>>E>> =>
import EffectEffect.const gen: {
<Eff extends Effect<any, any, any>, AEff>(
f: () => Generator<Eff, AEff, never>
): Effect<
AEff,
[Eff] extends [never]
? never
: [Eff] extends [
Effect<infer _A, infer E, infer _R>
]
? E
: never,
[Eff] extends [never]
? never
: [Eff] extends [
Effect<infer _A, infer _E, infer R>
]
? R
: never
>
<Self, Eff extends Effect<any, any, any>, AEff>(
options: { readonly self: Self },
f: (this: Self) => Generator<Eff, AEff, never>
): Effect<
AEff,
[Eff] extends [never]
? never
: [Eff] extends [
Effect<infer _A, infer E, infer _R>
]
? E
: never,
[Eff] extends [never]
? never
: [Eff] extends [
Effect<infer _A, infer _E, infer R>
]
? R
: never
>
}
const state: State<any, any>state = yield* import TxRefTxRef.const get: <A>(
self: TxRef<A>
) => Effect.Effect<A>
Reads the current value of the TxRef.
When to use
Use to read the current value of a TxRef.
Example (Reading transactional references)
import { Effect, TxRef } from "effect"
const program = Effect.gen(function*() {
const counter = yield* TxRef.make(42)
// Read the value within a transaction
const value = yield* Effect.tx(
TxRef.get(counter)
)
console.log(value) // 42
})
get(self: TxEnqueue<A, E>(parameter) self: {
strategy: "bounded" | "unbounded" | "dropping" | "sliding";
capacity: number;
items: TxChunk.TxChunk<any>;
stateRef: TxRef.TxRef<State<any, any>>;
toString: () => string;
toJSON: () => unknown;
}
TxQueueState.stateRef: TxRef.TxRef<State<any, any>>(property) TxQueueState.stateRef: {
version: number;
pending: Map<unknown, () => void>;
value: A;
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 state: State<any, any>state._tag: "Open" | "Closing" | "Done"_tag === "Done") {
// Return empty array only for halt causes (like Cause.Done)
if (isDoneCause<E>(cause: Cause.Cause<E>): booleanChecks whether a Cause contains any done errors.
When to use
Use when you need to test whether a pull failure cause represents normal
completion and only need a boolean result.
isDoneCause(const state: {
readonly _tag: "Done"
readonly cause: Cause.Cause<any>
}
cause: Cause.Cause<E>(property) 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 EffectEffect.const failCause: <E>(
cause: Cause.Cause<E>
) => Effect<never, E>
Creates an Effect that represents a failure with a specific Cause.
When to use
Use when you already have a full Cause and need to preserve defects,
interruptions, annotations, or combined failures in the effect's failure
channel.
Details
This function allows you to create effects that fail with complex error
structures, including multiple errors, defects, interruptions, and more.
Example (Failing with a full Cause)
import { Cause, Effect } from "effect"
const program = Effect.failCause(
Cause.fail("Network error")
)
Effect.runPromiseExit(program).then(console.log)
// Output: { _id: 'Exit', _tag: 'Failure', cause: ... }
failCause(const state: {
readonly _tag: "Done"
readonly cause: Cause.Cause<any>
}
cause: Cause.Cause<E>(property) 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;
}
const chunk: Chunk.Chunk<any>const chunk: {
length: number;
right: Chunk<A>;
left: Chunk<A>;
backing: Backing<A>;
depth: number;
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 TxChunkTxChunk.const get: <A>(
self: TxChunk<A>
) => Effect.Effect<Chunk.Chunk<A>>
Reads the current chunk from the TxChunk.
Example (Reading the current chunk)
import { Chunk, Effect, TxChunk } from "effect"
const program = Effect.gen(function*() {
const txChunk = yield* TxChunk.fromIterable([1, 2, 3])
// Read the current value within a transaction
const chunk = yield* TxChunk.get(txChunk)
console.log(Chunk.toReadonlyArray(chunk)) // [1, 2, 3]
// The value is tracked for conflict detection
const size = Chunk.size(chunk)
console.log(size) // 3
})
get(self: TxEnqueue<A, E>(parameter) self: {
strategy: "bounded" | "unbounded" | "dropping" | "sliding";
capacity: number;
items: TxChunk.TxChunk<any>;
stateRef: TxRef.TxRef<State<any, any>>;
toString: () => string;
toJSON: () => unknown;
}
TxQueueState.items: TxChunk.TxChunk<any>(property) TxQueueState.items: {
ref: TxRef.TxRef<Chunk.Chunk<A>>;
toString: () => string;
toJSON: () => unknown;
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 TxChunkTxChunk.const set: {
<A>(chunk: Chunk.Chunk<A>): (
self: TxChunk<A>
) => Effect.Effect<void>
<A>(
self: TxChunk<A>,
chunk: Chunk.Chunk<A>
): Effect.Effect<void>
}
self: TxEnqueue<A, E>(parameter) self: {
strategy: "bounded" | "unbounded" | "dropping" | "sliding";
capacity: number;
items: TxChunk.TxChunk<any>;
stateRef: TxRef.TxRef<State<any, any>>;
toString: () => string;
toJSON: () => unknown;
}
TxQueueState.items: TxChunk.TxChunk<any>(property) TxQueueState.items: {
ref: TxRef.TxRef<Chunk.Chunk<A>>;
toString: () => string;
toJSON: () => unknown;
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 ChunkChunk.const empty: <A = never>() => Chunk<A>Creates an empty Chunk.
Example (Creating an empty chunk)
import { Chunk } from "effect"
const emptyChunk = Chunk.empty()
console.log(Chunk.size(emptyChunk)) // 0
empty())
return import ChunkChunk.const toArray: <S extends Chunk<any>>(
self: S
) => S extends NonEmptyChunk<any>
? RA.NonEmptyArray<Chunk.Infer<S>>
: Array<Chunk.Infer<S>>
Converts a Chunk into an Array. If the provided Chunk is non-empty
(NonEmptyChunk), the function will return a NonEmptyArray, ensuring the
non-empty property is preserved.
Example (Converting chunks to mutable arrays)
import { Chunk } from "effect"
const chunk = Chunk.make(1, 2, 3)
const array = Chunk.toArray(chunk)
console.log(array) // [1, 2, 3]
console.log(Array.isArray(array)) // true
// With empty chunk
const emptyChunk = Chunk.empty<number>()
console.log(Chunk.toArray(emptyChunk)) // []
toArray(const chunk: Chunk.Chunk<any>const chunk: {
length: number;
right: Chunk<A>;
left: Chunk<A>;
backing: Backing<A>;
depth: number;
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;
}
Pipeable.pipe<Effect.Effect<any[], any, never>, Effect.Effect<any[], any, never>>(this: Effect.Effect<any[], any, never>, ab: (_: Effect.Effect<any[], any, never>) => Effect.Effect<any[], any, never>): Effect.Effect<any[], any, never> (+21 overloads)pipe(import EffectEffect.const tx: <A, E, R>(
effect: Effect<A, E, R>
) => Effect<A, E, Exclude<R, Transaction>>
Defines a transaction boundary. Transactions are "all or nothing" with respect to changes
made to transactional values (i.e. TxRef) that occur within the transaction body.
Details
If called inside an active transaction, tx composes with the current transaction and reuses
its journal and retry state instead of creating a nested boundary.
Effect transactions are optimistic with retry. A transaction is retried when
its body explicitly calls Effect.txRetry and any accessed transactional
value changes, or when any accessed transactional value changes because a
different transaction commits before the current one.
The outermost tx call creates the transaction boundary and commits or rolls back the full
composed transaction.
Example (Running a transaction)
import { Effect, TxRef } from "effect"
const program = Effect.gen(function*() {
const ref1 = yield* TxRef.make(0)
const ref2 = yield* TxRef.make(0)
// Nested tx calls compose into the same transaction
yield* Effect.tx(Effect.gen(function*() {
yield* TxRef.set(ref1, 10)
yield* Effect.tx(TxRef.set(ref2, 20))
const sum = (yield* TxRef.get(ref1)) + (yield* TxRef.get(ref2))
console.log(`Transaction sum: ${sum}`)
}))
console.log(`Final ref1: ${yield* TxRef.get(ref1)}`) // 10
console.log(`Final ref2: ${yield* TxRef.get(ref2)}`) // 20
})
tx)