<Key, A, R>(key: Key): <E>(
self: ScopedCache<Key, A, E, R>
) => Effect.Effect<Option.Option<A>>
<Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<
Option.Option<A>
>Retrieves the value associated with the specified key from the cache, only if it contains a resolved successful value.
When to use
Use to inspect an already-completed successful scoped cache entry without running or awaiting the lookup effect.
Details
Returns Option.some for a resolved successful entry. Returns Option.none
for missing, expired, failed, or still-pending entries.
export const const getSuccess: {
<Key, A, R>(key: Key): <E>(
self: ScopedCache<Key, A, E, R>
) => Effect.Effect<Option.Option<A>>
<Key, A, E, R>(
self: ScopedCache<Key, A, E, R>,
key: Key
): Effect.Effect<Option.Option<A>>
}
Retrieves the value associated with the specified key from the cache, only if
it contains a resolved successful value.
When to use
Use to inspect an already-completed successful scoped cache entry without
running or awaiting the lookup effect.
Details
Returns Option.some for a resolved successful entry. Returns Option.none
for missing, expired, failed, or still-pending entries.
getSuccess: {
<function (type parameter) Key in <Key, A, R>(key: Key): <E>(self: ScopedCache<Key, A, E, R>) => Effect.Effect<Option.Option<A>>Key, function (type parameter) A in <Key, A, R>(key: Key): <E>(self: ScopedCache<Key, A, E, R>) => Effect.Effect<Option.Option<A>>A, function (type parameter) R in <Key, A, R>(key: Key): <E>(self: ScopedCache<Key, A, E, R>) => Effect.Effect<Option.Option<A>>R>(key: Keykey: function (type parameter) Key in <Key, A, R>(key: Key): <E>(self: ScopedCache<Key, A, E, R>) => Effect.Effect<Option.Option<A>>Key): <function (type parameter) E in <E>(self: ScopedCache<Key, A, E, R>): Effect.Effect<Option.Option<A>>E>(self: ScopedCache<Key, A, E, R>(parameter) self: {
state: State<Key, A, E>;
capacity: number;
lookup: (key: Key) => Effect.Effect<A, E, R | Scope.Scope>;
timeToLive: (exit: Exit.Exit<A, E>, key: Key) => Duration.Duration;
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; <…;
}
interface ScopedCache<in out Key, in out A, in out E = never, out R = never>A scoped cache whose values are acquired by a lookup effect and stored in
per-entry scopes.
When to use
Use to cache values that acquire scoped resources and must release those
resources when entries expire, are evicted, or are invalidated.
Details
Concurrent requests for the same key share the same in-flight lookup.
Entries can expire based on the lookup exit, are evicted when capacity is
exceeded, and release their entry scopes when invalidated, evicted, expired,
or when the cache's owning scope closes.
ScopedCache<function (type parameter) Key in <Key, A, R>(key: Key): <E>(self: ScopedCache<Key, A, E, R>) => Effect.Effect<Option.Option<A>>Key, function (type parameter) A in <Key, A, R>(key: Key): <E>(self: ScopedCache<Key, A, E, R>) => Effect.Effect<Option.Option<A>>A, function (type parameter) E in <E>(self: ScopedCache<Key, A, E, R>): Effect.Effect<Option.Option<A>>E, function (type parameter) R in <Key, A, R>(key: Key): <E>(self: ScopedCache<Key, A, E, R>) => Effect.Effect<Option.Option<A>>R>) => 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<import OptionOption.type Option<A> = Option.None<A> | Option.Some<A>The Option data type represents optional values. An Option<A> is either
Some<A>, containing a value of type A, or None, representing absence.
When to use
Use to represent initial values that may not yet exist
- Returning from partial functions (not defined for all inputs)
- Managing optional fields in data structures
Namespace containing utility types for Option.
When to use
Use to access type-level helpers associated with Option.
Option<function (type parameter) A in <Key, A, R>(key: Key): <E>(self: ScopedCache<Key, A, E, R>) => Effect.Effect<Option.Option<A>>A>>
<function (type parameter) Key in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>>Key, function (type parameter) A in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>>A, function (type parameter) E in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>>E, function (type parameter) R in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>>R>(self: ScopedCache<Key, A, E, R>(parameter) self: {
state: State<Key, A, E>;
capacity: number;
lookup: (key: Key) => Effect.Effect<A, E, R | Scope.Scope>;
timeToLive: (exit: Exit.Exit<A, E>, key: Key) => Duration.Duration;
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; <…;
}
interface ScopedCache<in out Key, in out A, in out E = never, out R = never>A scoped cache whose values are acquired by a lookup effect and stored in
per-entry scopes.
When to use
Use to cache values that acquire scoped resources and must release those
resources when entries expire, are evicted, or are invalidated.
Details
Concurrent requests for the same key share the same in-flight lookup.
Entries can expire based on the lookup exit, are evicted when capacity is
exceeded, and release their entry scopes when invalidated, evicted, expired,
or when the cache's owning scope closes.
ScopedCache<function (type parameter) Key in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>>Key, function (type parameter) A in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>>A, function (type parameter) E in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>>E, function (type parameter) R in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>>R>, key: Keykey: function (type parameter) Key in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>>Key): 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<import OptionOption.type Option<A> = Option.None<A> | Option.Some<A>The Option data type represents optional values. An Option<A> is either
Some<A>, containing a value of type A, or None, representing absence.
When to use
Use to represent initial values that may not yet exist
- Returning from partial functions (not defined for all inputs)
- Managing optional fields in data structures
Namespace containing utility types for Option.
When to use
Use to access type-level helpers associated with Option.
Option<function (type parameter) A in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>>A>>
} = dual<(...args: Array<any>) => any, <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key) => Effect.Effect<Option.Option<A>>>(arity: 2, body: <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key) => Effect.Effect<Option.Option<A>>): ((...args: Array<any>) => any) & (<Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key) => Effect.Effect<Option.Option<A>>) (+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) Key in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>>Key, function (type parameter) A in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>>A, function (type parameter) E in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>>E, function (type parameter) R in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>>R>(self: ScopedCache<Key, A, E, R>(parameter) self: {
state: State<Key, A, E>;
capacity: number;
lookup: (key: Key) => Effect.Effect<A, E, R | Scope.Scope>;
timeToLive: (exit: Exit.Exit<A, E>, key: Key) => Duration.Duration;
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; <…;
}
interface ScopedCache<in out Key, in out A, in out E = never, out R = never>A scoped cache whose values are acquired by a lookup effect and stored in
per-entry scopes.
When to use
Use to cache values that acquire scoped resources and must release those
resources when entries expire, are evicted, or are invalidated.
Details
Concurrent requests for the same key share the same in-flight lookup.
Entries can expire based on the lookup exit, are evicted when capacity is
exceeded, and release their entry scopes when invalidated, evicted, expired,
or when the cache's owning scope closes.
ScopedCache<function (type parameter) Key in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>>Key, function (type parameter) A in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>>A, function (type parameter) E in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>>E, function (type parameter) R in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>>R>, key: Keykey: function (type parameter) Key in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>>Key): 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<import OptionOption.type Option<A> = Option.None<A> | Option.Some<A>The Option data type represents optional values. An Option<A> is either
Some<A>, containing a value of type A, or None, representing absence.
When to use
Use to represent initial values that may not yet exist
- Returning from partial functions (not defined for all inputs)
- Managing optional fields in data structures
Namespace containing utility types for Option.
When to use
Use to access type-level helpers associated with Option.
Option<function (type parameter) A in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>>A>> =>
import effecteffect.const uninterruptible: <A, E, R>(
self: Effect.Effect<A, E, R>
) => Effect.Effect<A, E, R>
import corecore.const withFiber: <
A,
E = never,
R = never
>(
evaluate: (
fiber: FiberImpl<unknown, unknown>
) => Effect.Effect<A, E, R>
) => Effect.Effect<A, E, R>
fiber: effect.FiberImpl<unknown, unknown>(parameter) fiber: {
id: number;
interruptible: boolean;
currentOpCount: number;
currentLoopCount: number;
_stack: Array<Primitive>;
_observers: Array<(exit: Exit.Exit<A, E>) => void>;
_exit: Exit.Exit<A, E> | undefined;
_currentExit: Exit.Exit<A, E> | undefined;
_children: Set<FiberImpl<any, any>> | undefined;
_interruptedCause: Cause.Cause<never> | undefined;
_yielded: Exit.Exit<any, any> | (() => void) | undefined;
context: Context.Context<never>;
currentScheduler: Scheduler.Scheduler;
currentTracerContext: Tracer.Tracer["context"];
currentSpan: Tracer.AnySpan | undefined;
currentLogLevel: LogLevel.LogLevel;
minimumLogLevel: LogLevel.LogLevel;
currentStackFrame: StackFrame | undefined;
runtimeMetrics: Metric.FiberRuntimeMetricsService | undefined;
maxOpsBeforeYield: number;
currentPreventYield: boolean;
_dispatcher: Scheduler.SchedulerDispatcher | undefined;
currentDispatcher: SchedulerDispatcher;
getRef: <X>(ref: Context.Reference<X>) => X;
addObserver: (cb: (exit: Exit.Exit<unknown, unknown>) => void) => () => void;
interruptUnsafe: (fiberId?: number | undefined, annotations?: Context.Context<never> | undefined) => void;
pollUnsafe: () => Exit.Exit<unknown, unknown> | undefined;
evaluate: (effect: core.Primitive) => void;
runLoop: (effect: core.Primitive) => typeof core.Yield | Exit.Exit<unknown, unknown>;
getCont: <S extends core.contA | core.contE>(symbol: S) => (core.Primitive & Record<S, (value: any, fiber: effect.FiberImpl) => core.Primitive>) | undefined;
yieldWith: (value: Exit.Exit<any, any> | (() => void)) => core.Yield;
children: () => Set<Fiber.Fiber<any, any>>;
pipe: () => unknown;
setContext: (context: Context.Context<never>) => void;
currentSpanLocal: Span | undefined;
}
import effecteffect.const map: {
<A, B>(f: (a: A) => B): <E, R>(
self: Effect.Effect<A, E, R>
) => Effect.Effect<B, E, R>
<A, E, R, B>(
self: Effect.Effect<A, E, R>,
f: (a: A) => B
): Effect.Effect<B, E, R>
}
const getImpl: <Key, A, E, R>(
self: ScopedCache<Key, A, E, R>,
key: Key,
fiber: Fiber.Fiber<any, any>,
isRead?: boolean
) => Effect.Effect<Entry<A, E> | undefined>
self: ScopedCache<Key, A, E, R>(parameter) self: {
state: State<Key, A, E>;
capacity: number;
lookup: (key: Key) => Effect.Effect<A, E, R | Scope.Scope>;
timeToLive: (exit: Exit.Exit<A, E>, key: Key) => Duration.Duration;
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; <…;
}
key: Keykey, fiber: effect.FiberImpl<unknown, unknown>(parameter) fiber: {
id: number;
interruptible: boolean;
currentOpCount: number;
currentLoopCount: number;
_stack: Array<Primitive>;
_observers: Array<(exit: Exit.Exit<A, E>) => void>;
_exit: Exit.Exit<A, E> | undefined;
_currentExit: Exit.Exit<A, E> | undefined;
_children: Set<FiberImpl<any, any>> | undefined;
_interruptedCause: Cause.Cause<never> | undefined;
_yielded: Exit.Exit<any, any> | (() => void) | undefined;
context: Context.Context<never>;
currentScheduler: Scheduler.Scheduler;
currentTracerContext: Tracer.Tracer["context"];
currentSpan: Tracer.AnySpan | undefined;
currentLogLevel: LogLevel.LogLevel;
minimumLogLevel: LogLevel.LogLevel;
currentStackFrame: StackFrame | undefined;
runtimeMetrics: Metric.FiberRuntimeMetricsService | undefined;
maxOpsBeforeYield: number;
currentPreventYield: boolean;
_dispatcher: Scheduler.SchedulerDispatcher | undefined;
currentDispatcher: SchedulerDispatcher;
getRef: <X>(ref: Context.Reference<X>) => X;
addObserver: (cb: (exit: Exit.Exit<unknown, unknown>) => void) => () => void;
interruptUnsafe: (fiberId?: number | undefined, annotations?: Context.Context<never> | undefined) => void;
pollUnsafe: () => Exit.Exit<unknown, unknown> | undefined;
evaluate: (effect: core.Primitive) => void;
runLoop: (effect: core.Primitive) => typeof core.Yield | Exit.Exit<unknown, unknown>;
getCont: <S extends core.contA | core.contE>(symbol: S) => (core.Primitive & Record<S, (value: any, fiber: effect.FiberImpl) => core.Primitive>) | undefined;
yieldWith: (value: Exit.Exit<any, any> | (() => void)) => core.Yield;
children: () => Set<Fiber.Fiber<any, any>>;
pipe: () => unknown;
setContext: (context: Context.Context<never>) => void;
currentSpanLocal: Span | undefined;
}
entry: Entry<A, E> | undefinedentry) => {
const const exit: Exit.Exit<A, E> | undefinedexit = entry: Entry<A, E> | undefinedentry?.Entry<A, E>.deferred: Deferred.Deferred<A, E>deferred.Deferred<A, E>.effect?: Effect<A, E>effect as 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<function (type parameter) A in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>>A, function (type parameter) E in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>>E> | undefined
if (const exit: Exit.Exit<A, E> | undefinedexit && import effecteffect.const exitIsSuccess: <A, E>(
self: Exit.Exit<A, E>
) => self is Exit.Success<A, E>
const exit: Exit.Exit<A, E>exit)) {
return import OptionOption.const some: <A>(value: A) => Option<A>Wraps the given value into an Option to represent its presence.
When to use
Use to wrap a known present value as Option
- Returning a successful result from a partial function
Details
- Always returns
Some<A>
- Does not filter
null or undefined; use
fromNullishOr
for that
Example (Wrapping a value)
import { Option } from "effect"
// ┌─── Option<number>
// ▼
const value = Option.some(1)
console.log(value)
// Output: { _id: 'Option', _tag: 'Some', value: 1 }
some(const exit: Exit.Success<A, E>const exit: {
_tag: "Success";
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; <…;
toString: () => string;
toJSON: () => unknown;
}
Success<A, E>.value: Avalue)
}
return import OptionOption.const none: <A = never>() => Option<A>Creates an Option representing the absence of a value.
When to use
Use to represent a missing or uninitialized value, such as returning "no
result" from a function.
Details
- Returns
Option<never>, which is a subtype of Option<A> for any A
- Always returns the same singleton instance
Example (Creating an empty Option)
import { Option } from "effect"
// ┌─── Option<never>
// ▼
const noValue = Option.none()
console.log(noValue)
// Output: { _id: 'Option', _tag: 'None' }
none()
}
)
)
)
)