<Key, A>(key: Key): <E, R>(
self: ScopedCache<Key, A, E, R>
) => Effect.Effect<Option.Option<A>, E>
<Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<
Option.Option<A>,
E
>Reads an existing unexpired cache entry without running the lookup function.
When to use
Use to read a scoped value only when it is already cached, without starting the lookup for missing or expired keys.
Details
Returns Option.none when the key is absent or expired. If an entry exists,
the effect waits for its cached result and returns Option.some(value) on
success, or fails with the cached lookup error.
export const const getOption: {
<Key, A>(key: Key): <E, R>(
self: ScopedCache<Key, A, E, R>
) => Effect.Effect<Option.Option<A>, E>
<Key, A, E, R>(
self: ScopedCache<Key, A, E, R>,
key: Key
): Effect.Effect<Option.Option<A>, E>
}
Reads an existing unexpired cache entry without running the lookup function.
When to use
Use to read a scoped value only when it is already cached, without starting
the lookup for missing or expired keys.
Details
Returns Option.none when the key is absent or expired. If an entry exists,
the effect waits for its cached result and returns Option.some(value) on
success, or fails with the cached lookup error.
getOption: {
<function (type parameter) Key in <Key, A>(key: Key): <E, R>(self: ScopedCache<Key, A, E, R>) => Effect.Effect<Option.Option<A>, E>Key, function (type parameter) A in <Key, A>(key: Key): <E, R>(self: ScopedCache<Key, A, E, R>) => Effect.Effect<Option.Option<A>, E>A>(key: Keykey: function (type parameter) Key in <Key, A>(key: Key): <E, R>(self: ScopedCache<Key, A, E, R>) => Effect.Effect<Option.Option<A>, E>Key): <function (type parameter) E in <E, R>(self: ScopedCache<Key, A, E, R>): Effect.Effect<Option.Option<A>, E>E, function (type parameter) R in <E, R>(self: ScopedCache<Key, A, E, R>): Effect.Effect<Option.Option<A>, E>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>(key: Key): <E, R>(self: ScopedCache<Key, A, E, R>) => Effect.Effect<Option.Option<A>, E>Key, function (type parameter) A in <Key, A>(key: Key): <E, R>(self: ScopedCache<Key, A, E, R>) => Effect.Effect<Option.Option<A>, E>A, function (type parameter) E in <E, R>(self: ScopedCache<Key, A, E, R>): Effect.Effect<Option.Option<A>, E>E, function (type parameter) R in <E, R>(self: ScopedCache<Key, A, E, R>): Effect.Effect<Option.Option<A>, E>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>(key: Key): <E, R>(self: ScopedCache<Key, A, E, R>) => Effect.Effect<Option.Option<A>, E>A>, function (type parameter) E in <E, R>(self: ScopedCache<Key, A, E, R>): Effect.Effect<Option.Option<A>, E>E>
<function (type parameter) Key in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>, E>Key, function (type parameter) A in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>, E>A, function (type parameter) E in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>, E>E, function (type parameter) R in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>, E>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>, E>Key, function (type parameter) A in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>, E>A, function (type parameter) E in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>, E>E, function (type parameter) R in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>, E>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>, E>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>, E>A>, function (type parameter) E in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>, E>E>
} = dual<(...args: Array<any>) => any, <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key) => Effect.Effect<Option.Option<A>, E>>(arity: 2, body: <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key) => Effect.Effect<Option.Option<A>, E>): ((...args: Array<any>) => any) & (<Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key) => Effect.Effect<Option.Option<A>, E>) (+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>, E>Key, function (type parameter) A in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>, E>A, function (type parameter) E in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>, E>E, function (type parameter) R in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>, E>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>, E>Key, function (type parameter) A in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>, E>A, function (type parameter) E in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>, E>E, function (type parameter) R in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>, E>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>, E>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>, E>A>, function (type parameter) E in <Key, A, E, R>(self: ScopedCache<Key, A, E, R>, key: Key): Effect.Effect<Option.Option<A>, E>E> =>
import effecteffect.const uninterruptibleMask: <A, E, R>(
f: (
restore: <A, E, R>(
effect: Effect.Effect<A, E, R>
) => Effect.Effect<A, E, R>
) => Effect.Effect<A, E, R>
) => Effect.Effect<A, E, R>
restore: <A, E, R>(
effect: 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 flatMap: {
<A, B, E2, R2>(
f: (a: A) => Effect.Effect<B, E2, R2>
): <E, R>(
self: Effect.Effect<A, E, R>
) => Effect.Effect<B, E | E2, R | R2>
<A, E, R, B, E2, R2>(
self: Effect.Effect<A, E, R>,
f: (a: A) => Effect.Effect<B, E2, R2>
): Effect.Effect<B, E | E2, R | R2>
}
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) => entry: Entry<A, E> | undefinedentry ? import effecteffect.const asSome: <A, E, R>(
self: Effect.Effect<A, E, R>
) => Effect.Effect<Option.Option<A>, E, R>
restore: <A, E, R>(
effect: Effect.Effect<A, E, R>
) => Effect.Effect<A, E, R>
import DeferredDeferred.await<A, E>(self: Deferred<A, E>): Effect<A, E>Retrieves the value of the Deferred, suspending the fiber running the
workflow until the result is available.
When to use
Use to wait for a Deferred to be completed and resume with its success,
failure, defect, or interruption.
Details
Awaiters observe the completion effect stored in the Deferred.
Example (Awaiting a Deferred value)
import { Deferred, Effect } from "effect"
const program = Effect.gen(function*() {
const deferred = yield* Deferred.make<number>()
yield* Deferred.succeed(deferred, 42)
const value = yield* Deferred.await(deferred)
console.log(value) // 42
})
await(entry: Entry<A, E>(parameter) entry: {
expiresAt: number | undefined;
deferred: Deferred.Deferred<A, E>;
scope: Scope.Closeable;
}
Entry<A, E>.deferred: Deferred.Deferred<A, E>(property) Entry<A, E>.deferred: {
effect: Effect<A, E>;
resumes: Array<(effect: Effect<A, E>) => void> | undefined;
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; <…;
}
import effecteffect.const succeedNone: Effect.Effect<
Option.Option<never>
>
const succeedNone: {
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;
}