<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
})
)export const 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: <function (type parameter) A in <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>
function (type parameter) E in <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>
function (type parameter) R in <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>
function (type parameter) R2 in <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>
acquire: Effect<A, E, R>(parameter) acquire: {
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 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) A in <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>
function (type parameter) E in <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>
function (type parameter) R in <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>
release: (
a: A,
exit: Exit.Exit<unknown, unknown>
) => Effect<unknown, never, R2>
a: Aa: function (type parameter) A in <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>
exit: Exit.Exit<unknown, unknown>exit: 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>) => 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, never, function (type parameter) R2 in <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>
options: | {
readonly interruptible?: boolean
}
| undefined
interruptible?: boolean | undefinedinterruptible?: boolean }
) => 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) A in <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>
function (type parameter) E in <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>
function (type parameter) R in <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>
function (type parameter) R2 in <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>
import internalinternal.const acquireRelease: <A, E, R, R2>(
acquire: Effect.Effect<A, E, R>,
release: (
a: A,
exit: Exit.Exit<unknown, unknown>
) => Effect.Effect<unknown, never, R2>,
options?: { readonly interruptible?: boolean }
) => Effect.Effect<A, E, R | R2 | Scope.Scope>