<E>(error: E): Effect<never, E>Creates an Effect that represents a recoverable error.
When to use
Use to explicitly signal a recoverable error in an Effect.
Details
The error keeps propagating unless it is handled. You can handle tagged errors with functions like catchTag or catchTags.
Example (Creating a failed effect)
import { Data, Effect } from "effect"
class OperationFailedError extends Data.TaggedError("OperationFailedError")<{}> {}
// ┌─── Effect<never, OperationFailedError, never>
// ▼
const failure = Effect.fail(
new OperationFailedError()
)export const const fail: <E>(
error: E
) => Effect<never, E>
Creates an Effect that represents a recoverable error.
When to use
Use to explicitly signal a recoverable error in an Effect.
Details
The error keeps propagating unless it is handled. You can handle tagged
errors with functions like
catchTag
or
catchTags
.
Example (Creating a failed effect)
import { Data, Effect } from "effect"
class OperationFailedError extends Data.TaggedError("OperationFailedError")<{}> {}
// ┌─── Effect<never, OperationFailedError, never>
// ▼
const failure = Effect.fail(
new OperationFailedError()
)
fail: <function (type parameter) E in <E>(error: E): Effect<never, E>E>(error: Eerror: function (type parameter) E in <E>(error: E): Effect<never, E>E) => 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<never, function (type parameter) E in <E>(error: E): Effect<never, E>E> = import internalinternal.const fail: <E>(
error: E
) => Effect.Effect<never, E>