<R>(
finalizer: (exit: Exit.Exit<unknown, unknown>) => Effect<void, never, R>
): Effect<void, never, R | Scope>Adds a finalizer to the current scope.
When to use
Use to register low-level cleanup in the current scope.
Details
The finalizer runs when the surrounding scope is closed and receives the
Exit value used to close the scope.
Example (Registering scope finalizers)
import { Console, Effect, Exit } from "effect"
const program = Effect.scoped(
Effect.gen(function*() {
// Add a finalizer that runs when the scope closes
yield* Effect.addFinalizer((exit) =>
Console.log(
Exit.isSuccess(exit)
? "Cleanup: Operation completed successfully"
: "Cleanup: Operation failed, cleaning up resources"
)
)
yield* Console.log("Performing main operation...")
// This could succeed or fail
return "operation result"
})
)
Effect.runPromise(program).then(console.log)
// Output:
// Performing main operation...
// Cleanup: Operation completed successfully
// operation resultexport const const addFinalizer: <R>(
finalizer: (
exit: Exit.Exit<unknown, unknown>
) => Effect<void, never, R>
) => Effect<void, never, R | Scope>
Adds a finalizer to the current scope.
When to use
Use to register low-level cleanup in the current scope.
Details
The finalizer runs when the surrounding scope is closed and receives the
Exit value used to close the scope.
Example (Registering scope finalizers)
import { Console, Effect, Exit } from "effect"
const program = Effect.scoped(
Effect.gen(function*() {
// Add a finalizer that runs when the scope closes
yield* Effect.addFinalizer((exit) =>
Console.log(
Exit.isSuccess(exit)
? "Cleanup: Operation completed successfully"
: "Cleanup: Operation failed, cleaning up resources"
)
)
yield* Console.log("Performing main operation...")
// This could succeed or fail
return "operation result"
})
)
Effect.runPromise(program).then(console.log)
// Output:
// Performing main operation...
// Cleanup: Operation completed successfully
// operation result
addFinalizer: <function (type parameter) R in <R>(finalizer: (exit: Exit.Exit<unknown, unknown>) => Effect<void, never, R>): Effect<void, never, R | Scope>R>(
finalizer: (
exit: Exit.Exit<unknown, unknown>
) => Effect<void, never, R>
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<void, never, function (type parameter) R in <R>(finalizer: (exit: Exit.Exit<unknown, unknown>) => Effect<void, never, R>): Effect<void, never, R | Scope>R>
) => 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, never, function (type parameter) R in <R>(finalizer: (exit: Exit.Exit<unknown, unknown>) => Effect<void, never, R>): Effect<void, never, R | Scope>R | Scope> = import internalinternal.const addFinalizer: <R>(
finalizer: (
exit: Exit.Exit<unknown, unknown>
) => Effect.Effect<void, never, R>
) => Effect.Effect<void, never, R | Scope.Scope>