<I, S, ES, RS>(
key: Context.Key<I, S>,
service: Effect.Effect<NoInfer<S>, ES, RS>
): <A, E, R>(
self: Stream<A, E, R>
) => Stream<A, E | ES, Exclude<R, I> | RS>
<A, E, R, I, S, ES, RS>(
self: Stream<A, E, R>,
key: Context.Key<I, S>,
service: Effect.Effect<NoInfer<S>, ES, RS>
): Stream<A, E | ES, Exclude<R, I> | RS>Provides a service to the stream using an effect, removing the requirement and adding the effect's error and environment.
Example (Providing a stream service effectfully)
import { Console, Context, Effect, Stream } from "effect"
class ApiConfig extends Context.Service<ApiConfig, { readonly baseUrl: string }>()("ApiConfig") {}
const stream = Stream.fromEffect(
Effect.gen(function*() {
const config = yield* Effect.service(ApiConfig)
return config.baseUrl
})
)
const withConfig = stream.pipe(
Stream.provideServiceEffect(
ApiConfig,
Effect.succeed({ baseUrl: "https://example.com" }).pipe(
Effect.tap(() => Console.log("Loading config..."))
)
)
)
const program = Stream.runCollect(withConfig).pipe(
Effect.flatMap((values) => Console.log(values))
)
Effect.runPromise(program)
// Output:
// Loading config...
// ["https://example.com"]services
Source effect/Stream.ts:1019317 lines
export const const provideServiceEffect: {
<I, S, ES, RS>(
key: Context.Key<I, S>,
service: Effect.Effect<NoInfer<S>, ES, RS>
): <A, E, R>(
self: Stream<A, E, R>
) => Stream<A, E | ES, Exclude<R, I> | RS>
<A, E, R, I, S, ES, RS>(
self: Stream<A, E, R>,
key: Context.Key<I, S>,
service: Effect.Effect<NoInfer<S>, ES, RS>
): Stream<A, E | ES, Exclude<R, I> | RS>
}
Provides a service to the stream using an effect, removing the requirement and adding the effect's error and environment.
Example (Providing a stream service effectfully)
import { Console, Context, Effect, Stream } from "effect"
class ApiConfig extends Context.Service<ApiConfig, { readonly baseUrl: string }>()("ApiConfig") {}
const stream = Stream.fromEffect(
Effect.gen(function*() {
const config = yield* Effect.service(ApiConfig)
return config.baseUrl
})
)
const withConfig = stream.pipe(
Stream.provideServiceEffect(
ApiConfig,
Effect.succeed({ baseUrl: "https://example.com" }).pipe(
Effect.tap(() => Console.log("Loading config..."))
)
)
)
const program = Stream.runCollect(withConfig).pipe(
Effect.flatMap((values) => Console.log(values))
)
Effect.runPromise(program)
// Output:
// Loading config...
// ["https://example.com"]
provideServiceEffect: {
<function (type parameter) I in <I, S, ES, RS>(key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): <A, E, R>(self: Stream<A, E, R>) => Stream<A, E | ES, Exclude<R, I> | RS>I, function (type parameter) S in <I, S, ES, RS>(key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): <A, E, R>(self: Stream<A, E, R>) => Stream<A, E | ES, Exclude<R, I> | RS>S, function (type parameter) ES in <I, S, ES, RS>(key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): <A, E, R>(self: Stream<A, E, R>) => Stream<A, E | ES, Exclude<R, I> | RS>ES, function (type parameter) RS in <I, S, ES, RS>(key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): <A, E, R>(self: Stream<A, E, R>) => Stream<A, E | ES, Exclude<R, I> | RS>RS>(
key: Context.Key<I, S>(parameter) key: {
Identifier: Identifier;
Service: Shape;
key: string;
stack: string | 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; <…;
toString: () => string;
toJSON: () => unknown;
}
import ContextContext.type Context.Key = /*unresolved*/ anyKey<function (type parameter) I in <I, S, ES, RS>(key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): <A, E, R>(self: Stream<A, E, R>) => Stream<A, E | ES, Exclude<R, I> | RS>I, function (type parameter) S in <I, S, ES, RS>(key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): <A, E, R>(self: Stream<A, E, R>) => Stream<A, E | ES, Exclude<R, I> | RS>S>,
service: Effect.Effect<NoInfer<S>, ES, RS>(parameter) service: {
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;
}
import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<type NoInfer<A> = [A][A extends any ? 0 : never]Prevents TypeScript from inferring a type parameter from a specific
position.
When to use
Use when a function parameter must match an inferred type without becoming
an inference source.
Details
The parameter using NoInfer must still match the inferred type.
Example (Controlling inference)
import type { Types } from "effect"
declare function withDefault<T>(value: T, fallback: Types.NoInfer<T>): T
// T is inferred as "a" | "b" from the first argument only
const result = withDefault<"a" | "b">("a", "b")
NoInfer<function (type parameter) S in <I, S, ES, RS>(key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): <A, E, R>(self: Stream<A, E, R>) => Stream<A, E | ES, Exclude<R, I> | RS>S>, function (type parameter) ES in <I, S, ES, RS>(key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): <A, E, R>(self: Stream<A, E, R>) => Stream<A, E | ES, Exclude<R, I> | RS>ES, function (type parameter) RS in <I, S, ES, RS>(key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): <A, E, R>(self: Stream<A, E, R>) => Stream<A, E | ES, Exclude<R, I> | RS>RS>
): <function (type parameter) A in <A, E, R>(self: Stream<A, E, R>): Stream<A, E | ES, Exclude<R, I> | RS>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>): Stream<A, E | ES, Exclude<R, I> | RS>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>): Stream<A, E | ES, Exclude<R, I> | RS>R>(
self: Stream<A, E, R>(parameter) self: {
channel: Channel.Channel<Arr.NonEmptyReadonlyArray<A>, E, void, unknown, unknown, unknown, R>;
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 Stream<out A, out E = never, out R = never>A Stream<A, E, R> describes a program that can emit many A values, fail
with E, and require R.
Details
Streams are pull-based with backpressure and emit chunks to amortize effect
evaluation. They support monadic composition and error handling similar to
Effect, adapted for multiple values.
Example (Creating and consuming streams)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
yield* Stream.make(1, 2, 3).pipe(
Stream.map((n) => n * 2),
Stream.runForEach((n) => Console.log(n))
)
})
Effect.runPromise(program)
// Output:
// 2
// 4
// 6
Stream<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>): Stream<A, E | ES, Exclude<R, I> | RS>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>): Stream<A, E | ES, Exclude<R, I> | RS>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>): Stream<A, E | ES, Exclude<R, I> | RS>R>
) => interface Stream<out A, out E = never, out R = never>A Stream<A, E, R> describes a program that can emit many A values, fail
with E, and require R.
Details
Streams are pull-based with backpressure and emit chunks to amortize effect
evaluation. They support monadic composition and error handling similar to
Effect, adapted for multiple values.
Example (Creating and consuming streams)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
yield* Stream.make(1, 2, 3).pipe(
Stream.map((n) => n * 2),
Stream.runForEach((n) => Console.log(n))
)
})
Effect.runPromise(program)
// Output:
// 2
// 4
// 6
Stream<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>): Stream<A, E | ES, Exclude<R, I> | RS>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>): Stream<A, E | ES, Exclude<R, I> | RS>E | function (type parameter) ES in <I, S, ES, RS>(key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): <A, E, R>(self: Stream<A, E, R>) => Stream<A, E | ES, Exclude<R, I> | RS>ES, type Exclude<T, U> = T extends U
? never
: T
Exclude from T those types that are assignable to U
Exclude<function (type parameter) R in <A, E, R>(self: Stream<A, E, R>): Stream<A, E | ES, Exclude<R, I> | RS>R, function (type parameter) I in <I, S, ES, RS>(key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): <A, E, R>(self: Stream<A, E, R>) => Stream<A, E | ES, Exclude<R, I> | RS>I> | function (type parameter) RS in <I, S, ES, RS>(key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): <A, E, R>(self: Stream<A, E, R>) => Stream<A, E | ES, Exclude<R, I> | RS>RS>
<function (type parameter) A in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>A, function (type parameter) E in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>E, function (type parameter) R in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>R, function (type parameter) I in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>I, function (type parameter) S in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>S, function (type parameter) ES in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>ES, function (type parameter) RS in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>RS>(
self: Stream<A, E, R>(parameter) self: {
channel: Channel.Channel<Arr.NonEmptyReadonlyArray<A>, E, void, unknown, unknown, unknown, R>;
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 Stream<out A, out E = never, out R = never>A Stream<A, E, R> describes a program that can emit many A values, fail
with E, and require R.
Details
Streams are pull-based with backpressure and emit chunks to amortize effect
evaluation. They support monadic composition and error handling similar to
Effect, adapted for multiple values.
Example (Creating and consuming streams)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
yield* Stream.make(1, 2, 3).pipe(
Stream.map((n) => n * 2),
Stream.runForEach((n) => Console.log(n))
)
})
Effect.runPromise(program)
// Output:
// 2
// 4
// 6
Stream<function (type parameter) A in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>A, function (type parameter) E in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>E, function (type parameter) R in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>R>,
key: Context.Key<I, S>(parameter) key: {
Identifier: Identifier;
Service: Shape;
key: string;
stack: string | 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; <…;
toString: () => string;
toJSON: () => unknown;
}
import ContextContext.type Context.Key = /*unresolved*/ anyKey<function (type parameter) I in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>I, function (type parameter) S in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>S>,
service: Effect.Effect<NoInfer<S>, ES, RS>(parameter) service: {
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;
}
import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<type NoInfer<A> = [A][A extends any ? 0 : never]Prevents TypeScript from inferring a type parameter from a specific
position.
When to use
Use when a function parameter must match an inferred type without becoming
an inference source.
Details
The parameter using NoInfer must still match the inferred type.
Example (Controlling inference)
import type { Types } from "effect"
declare function withDefault<T>(value: T, fallback: Types.NoInfer<T>): T
// T is inferred as "a" | "b" from the first argument only
const result = withDefault<"a" | "b">("a", "b")
NoInfer<function (type parameter) S in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>S>, function (type parameter) ES in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>ES, function (type parameter) RS in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>RS>
): interface Stream<out A, out E = never, out R = never>A Stream<A, E, R> describes a program that can emit many A values, fail
with E, and require R.
Details
Streams are pull-based with backpressure and emit chunks to amortize effect
evaluation. They support monadic composition and error handling similar to
Effect, adapted for multiple values.
Example (Creating and consuming streams)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
yield* Stream.make(1, 2, 3).pipe(
Stream.map((n) => n * 2),
Stream.runForEach((n) => Console.log(n))
)
})
Effect.runPromise(program)
// Output:
// 2
// 4
// 6
Stream<function (type parameter) A in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>A, function (type parameter) E in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>E | function (type parameter) ES in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>ES, type Exclude<T, U> = T extends U
? never
: T
Exclude from T those types that are assignable to U
Exclude<function (type parameter) R in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>R, function (type parameter) I in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>I> | function (type parameter) RS in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>RS>
} = import dualdual(3, <function (type parameter) A in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>A, function (type parameter) E in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>E, function (type parameter) R in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>R, function (type parameter) I in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>I, function (type parameter) S in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>S, function (type parameter) ES in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>ES, function (type parameter) RS in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>RS>(
self: Stream<A, E, R>(parameter) self: {
channel: Channel.Channel<Arr.NonEmptyReadonlyArray<A>, E, void, unknown, unknown, unknown, R>;
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 Stream<out A, out E = never, out R = never>A Stream<A, E, R> describes a program that can emit many A values, fail
with E, and require R.
Details
Streams are pull-based with backpressure and emit chunks to amortize effect
evaluation. They support monadic composition and error handling similar to
Effect, adapted for multiple values.
Example (Creating and consuming streams)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
yield* Stream.make(1, 2, 3).pipe(
Stream.map((n) => n * 2),
Stream.runForEach((n) => Console.log(n))
)
})
Effect.runPromise(program)
// Output:
// 2
// 4
// 6
Stream<function (type parameter) A in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>A, function (type parameter) E in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>E, function (type parameter) R in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>R>,
key: Context.Key<I, S>(parameter) key: {
Identifier: Identifier;
Service: Shape;
key: string;
stack: string | 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; <…;
toString: () => string;
toJSON: () => unknown;
}
import ContextContext.type Context.Key = /*unresolved*/ anyKey<function (type parameter) I in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>I, function (type parameter) S in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>S>,
service: Effect.Effect<NoInfer<S>, ES, RS>(parameter) service: {
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;
}
import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<type NoInfer<A> = [A][A extends any ? 0 : never]Prevents TypeScript from inferring a type parameter from a specific
position.
When to use
Use when a function parameter must match an inferred type without becoming
an inference source.
Details
The parameter using NoInfer must still match the inferred type.
Example (Controlling inference)
import type { Types } from "effect"
declare function withDefault<T>(value: T, fallback: Types.NoInfer<T>): T
// T is inferred as "a" | "b" from the first argument only
const result = withDefault<"a" | "b">("a", "b")
NoInfer<function (type parameter) S in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>S>, function (type parameter) ES in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>ES, function (type parameter) RS in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>RS>
): interface Stream<out A, out E = never, out R = never>A Stream<A, E, R> describes a program that can emit many A values, fail
with E, and require R.
Details
Streams are pull-based with backpressure and emit chunks to amortize effect
evaluation. They support monadic composition and error handling similar to
Effect, adapted for multiple values.
Example (Creating and consuming streams)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
yield* Stream.make(1, 2, 3).pipe(
Stream.map((n) => n * 2),
Stream.runForEach((n) => Console.log(n))
)
})
Effect.runPromise(program)
// Output:
// 2
// 4
// 6
Stream<function (type parameter) A in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>A, function (type parameter) E in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>E | function (type parameter) ES in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>ES, type Exclude<T, U> = T extends U
? never
: T
Exclude from T those types that are assignable to U
Exclude<function (type parameter) R in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>R, function (type parameter) I in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>I> | function (type parameter) RS in <A, E, R, I, S, ES, RS>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: Effect.Effect<NoInfer<S>, ES, RS>): Stream<A, E | ES, Exclude<R, I> | RS>RS> => const fromChannel: <
Arr extends Arr.NonEmptyReadonlyArray<any>,
E,
R
>(
channel: Channel.Channel<
Arr,
E,
void,
unknown,
unknown,
unknown,
R
>
) => Stream<
Arr extends Arr.NonEmptyReadonlyArray<infer A>
? A
: never,
E,
R
>
Creates a stream from a array-emitting Channel.
Example (Creating a stream from an array-emitting channel)
import { Channel, Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const channel = Channel.succeed([1, 2, 3] as const)
const stream = Stream.fromChannel(channel)
const result = yield* Stream.runCollect(stream)
yield* Console.log(result)
})
// Output: [ 1, 2, 3 ]
fromChannel(import ChannelChannel.provideServiceEffect(self: Stream<A, E, R>(parameter) self: {
channel: Channel.Channel<Arr.NonEmptyReadonlyArray<A>, E, void, unknown, unknown, unknown, R>;
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; <…;
}
Stream<out A, out E = never, out R = never>.channel: Channel.Channel<Arr.NonEmptyReadonlyArray<A>, E, void, unknown, unknown, unknown, R>(property) Stream<out A, out E = never, out R = never>.channel: {
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: Context.Key<I, S>(parameter) key: {
Identifier: Identifier;
Service: Shape;
key: string;
stack: string | 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; <…;
toString: () => string;
toJSON: () => unknown;
}
service: Effect.Effect<NoInfer<S>, ES, RS>(parameter) service: {
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;
}
Referenced by 1 symbols