<Z>(
release: (
z: Z,
e: Exit.Exit<unknown, unknown>
) => Effect.Effect<unknown>
): <E, R>(
self: Effect.Effect<Z, E, R>
) => Channel<Z, E, void, unknown, unknown, unknown, R>
<Z, E, R>(
self: Effect.Effect<Z, E, R>,
release: (
z: Z,
e: Exit.Exit<unknown, unknown>
) => Effect.Effect<unknown>
): Channel<Z, E, void, unknown, unknown, unknown, R>Acquires a resource, emits the acquired value as a single channel element,
and registers release in the channel scope.
Details
The release action runs when the channel scope closes and receives the scope
exit. If acquisition fails, no element is emitted and release is not
registered.
Example (Managing resources with acquire-release)
import { Channel, Effect } from "effect"
const channel = Channel.acquireRelease(
Effect.succeed("resource"),
(resource, exit) => Effect.log(`Released: ${resource}`)
)export const const acquireRelease: {
<Z>(
release: (
z: Z,
e: Exit.Exit<unknown, unknown>
) => Effect.Effect<unknown>
): <E, R>(
self: Effect.Effect<Z, E, R>
) => Channel<
Z,
E,
void,
unknown,
unknown,
unknown,
R
>
<Z, E, R>(
self: Effect.Effect<Z, E, R>,
release: (
z: Z,
e: Exit.Exit<unknown, unknown>
) => Effect.Effect<unknown>
): Channel<
Z,
E,
void,
unknown,
unknown,
unknown,
R
>
}
Acquires a resource, emits the acquired value as a single channel element,
and registers release in the channel scope.
Details
The release action runs when the channel scope closes and receives the scope
exit. If acquisition fails, no element is emitted and release is not
registered.
Example (Managing resources with acquire-release)
import { Channel, Effect } from "effect"
const channel = Channel.acquireRelease(
Effect.succeed("resource"),
(resource, exit) => Effect.log(`Released: ${resource}`)
)
acquireRelease: {
<function (type parameter) Z in <Z>(release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>): <E, R>(self: Effect.Effect<Z, E, R>) => Channel<Z, E, void, unknown, unknown, unknown, R>Z>(
release: (
z: Z,
e: Exit.Exit<unknown, unknown>
) => Effect.Effect<unknown>
z: Zz: function (type parameter) Z in <Z>(release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>): <E, R>(self: Effect.Effect<Z, E, R>) => Channel<Z, E, void, unknown, unknown, unknown, R>Z, e: Exit.Exit<unknown, unknown>e: import ExitExit.type Exit<A, E = never> = Exit.Success<A, E> | Exit.Failure<A, E>Represents the result of an Effect computation.
When to use
Use when you need to synchronously inspect whether an Effect computation
succeeded or failed.
Details
An Exit<A, E> is either Success<A, E> containing a value of type A, or
Failure<A, E> containing a Cause<E> describing why the computation
failed.
Since Exit is also an Effect, you can yield it inside Effect.gen.
Example (Pattern matching on an Exit)
import { Exit } from "effect"
const success: Exit.Exit<number> = Exit.succeed(42)
const failure: Exit.Exit<number, string> = Exit.fail("error")
const result = Exit.match(success, {
onSuccess: (value) => `Got value: ${value}`,
onFailure: (cause) => `Got error: ${cause}`
})
Namespace containing helper types shared by Exit values.
When to use
Use to reference helper types that describe the shared structure of Exit
values.
Exit<unknown, unknown>) => 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<unknown>
): <function (type parameter) E in <E, R>(self: Effect.Effect<Z, E, R>): Channel<Z, E, void, unknown, unknown, unknown, R>E, function (type parameter) R in <E, R>(self: Effect.Effect<Z, E, R>): Channel<Z, E, void, unknown, unknown, unknown, R>R>(self: Effect.Effect<Z, E, R>(parameter) self: {
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.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<function (type parameter) Z in <Z>(release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>): <E, R>(self: Effect.Effect<Z, E, R>) => Channel<Z, E, void, unknown, unknown, unknown, R>Z, function (type parameter) E in <E, R>(self: Effect.Effect<Z, E, R>): Channel<Z, E, void, unknown, unknown, unknown, R>E, function (type parameter) R in <E, R>(self: Effect.Effect<Z, E, R>): Channel<Z, E, void, unknown, unknown, unknown, R>R>) => interface Channel<out OutElem, out OutErr = never, out OutDone = void, in InElem = unknown, in InErr = unknown, in InDone = unknown, out Env = never>A Channel is a nexus of I/O operations, which supports both reading and
writing. A channel may read values of type InElem and write values of type
OutElem. When the channel finishes, it yields a value of type OutDone. A
channel may fail with a value of type OutErr.
Details
Channels are the foundation of Streams: both streams and sinks are built on
channels. Most users shouldn't have to use channels directly, as streams and
sinks are much more convenient and cover all common use cases. However, when
adding new stream and sink operators, or doing something highly specialized,
it may be useful to use channels directly.
Channels compose in a variety of ways:
- Piping: One channel can be piped to another channel, assuming the
input type of the second is the same as the output type of the first.
- Sequencing: The terminal value of one channel can be used to create
another channel, and both the first channel and the function that makes
the second channel can be composed into a channel.
- Concatenating: The output of one channel can be used to create other
channels, which are all concatenated together. The first channel and the
function that makes the other channels can be composed into a channel.
Example (Typing channels)
import type { Channel } from "effect"
// A channel that outputs numbers and requires no environment
type NumberChannel = Channel.Channel<number>
// A channel that outputs strings, can fail with Error, completes with boolean
type StringChannel = Channel.Channel<string, Error, boolean>
// A channel with all type parameters specified
type FullChannel = Channel.Channel<
string, // OutElem - output elements
Error, // OutErr - output errors
number, // OutDone - completion value
number, // InElem - input elements
string, // InErr - input errors
boolean, // InDone - input completion
{ db: string } // Env - required environment
>
Channel<function (type parameter) Z in <Z>(release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>): <E, R>(self: Effect.Effect<Z, E, R>) => Channel<Z, E, void, unknown, unknown, unknown, R>Z, function (type parameter) E in <E, R>(self: Effect.Effect<Z, E, R>): Channel<Z, E, void, unknown, unknown, unknown, R>E, void, unknown, unknown, unknown, function (type parameter) R in <E, R>(self: Effect.Effect<Z, E, R>): Channel<Z, E, void, unknown, unknown, unknown, R>R>
<function (type parameter) Z in <Z, E, R>(self: Effect.Effect<Z, E, R>, release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>): Channel<Z, E, void, unknown, unknown, unknown, R>Z, function (type parameter) E in <Z, E, R>(self: Effect.Effect<Z, E, R>, release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>): Channel<Z, E, void, unknown, unknown, unknown, R>E, function (type parameter) R in <Z, E, R>(self: Effect.Effect<Z, E, R>, release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>): Channel<Z, E, void, unknown, unknown, unknown, R>R>(
self: Effect.Effect<Z, E, R>(parameter) self: {
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.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<function (type parameter) Z in <Z, E, R>(self: Effect.Effect<Z, E, R>, release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>): Channel<Z, E, void, unknown, unknown, unknown, R>Z, function (type parameter) E in <Z, E, R>(self: Effect.Effect<Z, E, R>, release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>): Channel<Z, E, void, unknown, unknown, unknown, R>E, function (type parameter) R in <Z, E, R>(self: Effect.Effect<Z, E, R>, release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>): Channel<Z, E, void, unknown, unknown, unknown, R>R>,
release: (
z: Z,
e: Exit.Exit<unknown, unknown>
) => Effect.Effect<unknown>
z: Zz: function (type parameter) Z in <Z, E, R>(self: Effect.Effect<Z, E, R>, release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>): Channel<Z, E, void, unknown, unknown, unknown, R>Z, e: Exit.Exit<unknown, unknown>e: import ExitExit.type Exit<A, E = never> = Exit.Success<A, E> | Exit.Failure<A, E>Represents the result of an Effect computation.
When to use
Use when you need to synchronously inspect whether an Effect computation
succeeded or failed.
Details
An Exit<A, E> is either Success<A, E> containing a value of type A, or
Failure<A, E> containing a Cause<E> describing why the computation
failed.
Since Exit is also an Effect, you can yield it inside Effect.gen.
Example (Pattern matching on an Exit)
import { Exit } from "effect"
const success: Exit.Exit<number> = Exit.succeed(42)
const failure: Exit.Exit<number, string> = Exit.fail("error")
const result = Exit.match(success, {
onSuccess: (value) => `Got value: ${value}`,
onFailure: (cause) => `Got error: ${cause}`
})
Namespace containing helper types shared by Exit values.
When to use
Use to reference helper types that describe the shared structure of Exit
values.
Exit<unknown, unknown>) => 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<unknown>
): interface Channel<out OutElem, out OutErr = never, out OutDone = void, in InElem = unknown, in InErr = unknown, in InDone = unknown, out Env = never>A Channel is a nexus of I/O operations, which supports both reading and
writing. A channel may read values of type InElem and write values of type
OutElem. When the channel finishes, it yields a value of type OutDone. A
channel may fail with a value of type OutErr.
Details
Channels are the foundation of Streams: both streams and sinks are built on
channels. Most users shouldn't have to use channels directly, as streams and
sinks are much more convenient and cover all common use cases. However, when
adding new stream and sink operators, or doing something highly specialized,
it may be useful to use channels directly.
Channels compose in a variety of ways:
- Piping: One channel can be piped to another channel, assuming the
input type of the second is the same as the output type of the first.
- Sequencing: The terminal value of one channel can be used to create
another channel, and both the first channel and the function that makes
the second channel can be composed into a channel.
- Concatenating: The output of one channel can be used to create other
channels, which are all concatenated together. The first channel and the
function that makes the other channels can be composed into a channel.
Example (Typing channels)
import type { Channel } from "effect"
// A channel that outputs numbers and requires no environment
type NumberChannel = Channel.Channel<number>
// A channel that outputs strings, can fail with Error, completes with boolean
type StringChannel = Channel.Channel<string, Error, boolean>
// A channel with all type parameters specified
type FullChannel = Channel.Channel<
string, // OutElem - output elements
Error, // OutErr - output errors
number, // OutDone - completion value
number, // InElem - input elements
string, // InErr - input errors
boolean, // InDone - input completion
{ db: string } // Env - required environment
>
Channel<function (type parameter) Z in <Z, E, R>(self: Effect.Effect<Z, E, R>, release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>): Channel<Z, E, void, unknown, unknown, unknown, R>Z, function (type parameter) E in <Z, E, R>(self: Effect.Effect<Z, E, R>, release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>): Channel<Z, E, void, unknown, unknown, unknown, R>E, void, unknown, unknown, unknown, function (type parameter) R in <Z, E, R>(self: Effect.Effect<Z, E, R>, release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>): Channel<Z, E, void, unknown, unknown, unknown, R>R>
} = dual<(...args: Array<any>) => any, <Z, E, R>(self: Effect.Effect<Z, E, R>, release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>) => Channel<Z, E, void, unknown, unknown, unknown, R>>(arity: 2, body: <Z, E, R>(self: Effect.Effect<Z, E, R>, release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>) => Channel<Z, E, void, unknown, unknown, unknown, R>): ((...args: Array<any>) => any) & (<Z, E, R>(self: Effect.Effect<Z, E, R>, release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>) => Channel<Z, E, void, unknown, unknown, unknown, R>) (+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(2, <function (type parameter) Z in <Z, E, R>(self: Effect.Effect<Z, E, R>, release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>): Channel<Z, E, void, unknown, unknown, unknown, R>Z, function (type parameter) E in <Z, E, R>(self: Effect.Effect<Z, E, R>, release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>): Channel<Z, E, void, unknown, unknown, unknown, R>E, function (type parameter) R in <Z, E, R>(self: Effect.Effect<Z, E, R>, release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>): Channel<Z, E, void, unknown, unknown, unknown, R>R>(
self: Effect.Effect<Z, E, R>(parameter) self: {
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.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<function (type parameter) Z in <Z, E, R>(self: Effect.Effect<Z, E, R>, release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>): Channel<Z, E, void, unknown, unknown, unknown, R>Z, function (type parameter) E in <Z, E, R>(self: Effect.Effect<Z, E, R>, release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>): Channel<Z, E, void, unknown, unknown, unknown, R>E, function (type parameter) R in <Z, E, R>(self: Effect.Effect<Z, E, R>, release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>): Channel<Z, E, void, unknown, unknown, unknown, R>R>,
release: (
z: Z,
e: Exit.Exit<unknown, unknown>
) => Effect.Effect<unknown>
z: Zz: function (type parameter) Z in <Z, E, R>(self: Effect.Effect<Z, E, R>, release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>): Channel<Z, E, void, unknown, unknown, unknown, R>Z, e: Exit.Exit<unknown, unknown>e: import ExitExit.type Exit<A, E = never> = Exit.Success<A, E> | Exit.Failure<A, E>Represents the result of an Effect computation.
When to use
Use when you need to synchronously inspect whether an Effect computation
succeeded or failed.
Details
An Exit<A, E> is either Success<A, E> containing a value of type A, or
Failure<A, E> containing a Cause<E> describing why the computation
failed.
Since Exit is also an Effect, you can yield it inside Effect.gen.
Example (Pattern matching on an Exit)
import { Exit } from "effect"
const success: Exit.Exit<number> = Exit.succeed(42)
const failure: Exit.Exit<number, string> = Exit.fail("error")
const result = Exit.match(success, {
onSuccess: (value) => `Got value: ${value}`,
onFailure: (cause) => `Got error: ${cause}`
})
Namespace containing helper types shared by Exit values.
When to use
Use to reference helper types that describe the shared structure of Exit
values.
Exit<unknown, unknown>) => 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<unknown>
): interface Channel<out OutElem, out OutErr = never, out OutDone = void, in InElem = unknown, in InErr = unknown, in InDone = unknown, out Env = never>A Channel is a nexus of I/O operations, which supports both reading and
writing. A channel may read values of type InElem and write values of type
OutElem. When the channel finishes, it yields a value of type OutDone. A
channel may fail with a value of type OutErr.
Details
Channels are the foundation of Streams: both streams and sinks are built on
channels. Most users shouldn't have to use channels directly, as streams and
sinks are much more convenient and cover all common use cases. However, when
adding new stream and sink operators, or doing something highly specialized,
it may be useful to use channels directly.
Channels compose in a variety of ways:
- Piping: One channel can be piped to another channel, assuming the
input type of the second is the same as the output type of the first.
- Sequencing: The terminal value of one channel can be used to create
another channel, and both the first channel and the function that makes
the second channel can be composed into a channel.
- Concatenating: The output of one channel can be used to create other
channels, which are all concatenated together. The first channel and the
function that makes the other channels can be composed into a channel.
Example (Typing channels)
import type { Channel } from "effect"
// A channel that outputs numbers and requires no environment
type NumberChannel = Channel.Channel<number>
// A channel that outputs strings, can fail with Error, completes with boolean
type StringChannel = Channel.Channel<string, Error, boolean>
// A channel with all type parameters specified
type FullChannel = Channel.Channel<
string, // OutElem - output elements
Error, // OutErr - output errors
number, // OutDone - completion value
number, // InElem - input elements
string, // InErr - input errors
boolean, // InDone - input completion
{ db: string } // Env - required environment
>
Channel<function (type parameter) Z in <Z, E, R>(self: Effect.Effect<Z, E, R>, release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>): Channel<Z, E, void, unknown, unknown, unknown, R>Z, function (type parameter) E in <Z, E, R>(self: Effect.Effect<Z, E, R>, release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>): Channel<Z, E, void, unknown, unknown, unknown, R>E, void, unknown, unknown, unknown, function (type parameter) R in <Z, E, R>(self: Effect.Effect<Z, E, R>, release: (z: Z, e: Exit.Exit<unknown, unknown>) => Effect.Effect<unknown>): Channel<Z, E, void, unknown, unknown, unknown, R>R> =>
const unwrap: <
OutElem,
OutErr,
OutDone,
InElem,
InErr,
InDone,
R2,
E,
R
>(
channel: Effect.Effect<
Channel<
OutElem,
OutErr,
OutDone,
InElem,
InErr,
InDone,
R2
>,
E,
R
>
) => Channel<
OutElem,
E | OutErr,
OutDone,
InElem,
InErr,
InDone,
Exclude<R, Scope.Scope> | R2
>
Constructs a Channel from a scoped effect that will result in a
Channel if successful.
Example (Unwrapping channel effects)
import { Channel, Data, Effect } from "effect"
class UnwrapError extends Data.TaggedError("UnwrapError")<{
readonly reason: string
}> {}
// Create an effect that produces a channel
const channelEffect = Effect.succeed(
Channel.fromIterable([1, 2, 3])
)
// Unwrap the effect to get the channel
const unwrappedChannel = Channel.unwrap(channelEffect)
// The resulting channel outputs: 1, 2, 3
unwrap(import EffectEffect.const map: {
<A, B>(f: (a: A) => B): <E, R>(
self: Effect<A, E, R>
) => Effect<B, E, R>
<A, E, R, B>(
self: Effect<A, E, R>,
f: (a: A) => B
): Effect<B, E, R>
}
import EffectEffect.const acquireRelease: <A, E, R, R2>(
acquire: Effect<A, E, R>,
release: (
a: A,
exit: Exit.Exit<unknown, unknown>
) => Effect<unknown, never, R2>,
options?: { readonly interruptible?: boolean }
) => Effect<A, E, R | R2 | Scope>
Constructs a scoped resource from an acquisition effect and a release
finalizer.
When to use
Use to acquire a scoped resource with an explicit release finalizer.
Details
If acquisition succeeds, the release finalizer is added to the current scope
and is guaranteed to run when that scope closes. The finalizer receives the
Exit value used to close the scope.
By default, acquisition is protected by an uninterruptible region. Pass
{ interruptible: true } to allow the acquisition effect to be interrupted.
Example (Acquiring and releasing a resource)
import { Console, Effect, Exit } from "effect"
// Simulate a resource that needs cleanup
interface FileHandle {
readonly path: string
readonly content: string
}
// Acquire a file handle
const acquire = Effect.gen(function*() {
yield* Console.log("Opening file")
return { path: "/tmp/file.txt", content: "file content" }
})
// Release the file handle
const release = (handle: FileHandle, exit: Exit.Exit<unknown, unknown>) =>
Console.log(
`Closing file ${handle.path} with exit: ${
Exit.isSuccess(exit) ? "success" : "failure"
}`
)
// Create a scoped resource
const resource = Effect.acquireRelease(acquire, release)
// Use the resource within a scope
const program = Effect.scoped(
Effect.gen(function*() {
const handle = yield* resource
yield* Console.log(`Using file: ${handle.path}`)
return handle.content
})
)
acquireRelease(self: Effect.Effect<Z, E, R>(parameter) self: {
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;
}
release: (
z: Z,
e: Exit.Exit<unknown, unknown>
) => Effect.Effect<unknown>
const succeed: <A>(value: A) => Channel<A>Creates a Channel that emits a single value and then ends.
Example (Creating channels that succeed)
import { Channel } from "effect"
const channel = Channel.succeed(42)
// Emits: 42
succeed
)))