<I, S>(key: Context.Key<I, S>, service: NoInfer<S>): <A, E, R>(
self: Stream<A, E, R>
) => Stream<A, E, Exclude<R, I>>
<A, E, R, I, S>(
self: Stream<A, E, R>,
key: Context.Key<I, S>,
service: NoInfer<S>
): Stream<A, E, Exclude<R, I>>Provides the stream with a single required service, eliminating that requirement from its environment.
Example (Providing a stream service)
import { Console, Context, Effect, Stream } from "effect"
class Greeter extends Context.Service<Greeter, {
greet: (name: string) => string
}>()("Greeter") {}
const stream = Stream.fromEffect(
Effect.service(Greeter).pipe(
Effect.map((greeter) => greeter.greet("Ada"))
)
)
const program = Effect.gen(function*() {
const collected = yield* Stream.runCollect(
stream.pipe(
Stream.provideService(Greeter, {
greet: (name) => `Hello, ${name}`
})
)
)
yield* Console.log(collected)
})
Effect.runPromise(program)
//=> ["Hello, Ada"]services
Source effect/Stream.ts:1013617 lines
export const const provideService: {
<I, S>(
key: Context.Key<I, S>,
service: NoInfer<S>
): <A, E, R>(
self: Stream<A, E, R>
) => Stream<A, E, Exclude<R, I>>
<A, E, R, I, S>(
self: Stream<A, E, R>,
key: Context.Key<I, S>,
service: NoInfer<S>
): Stream<A, E, Exclude<R, I>>
}
Provides the stream with a single required service, eliminating that
requirement from its environment.
Example (Providing a stream service)
import { Console, Context, Effect, Stream } from "effect"
class Greeter extends Context.Service<Greeter, {
greet: (name: string) => string
}>()("Greeter") {}
const stream = Stream.fromEffect(
Effect.service(Greeter).pipe(
Effect.map((greeter) => greeter.greet("Ada"))
)
)
const program = Effect.gen(function*() {
const collected = yield* Stream.runCollect(
stream.pipe(
Stream.provideService(Greeter, {
greet: (name) => `Hello, ${name}`
})
)
)
yield* Console.log(collected)
})
Effect.runPromise(program)
//=> ["Hello, Ada"]
provideService: {
<function (type parameter) I in <I, S>(key: Context.Key<I, S>, service: NoInfer<S>): <A, E, R>(self: Stream<A, E, R>) => Stream<A, E, Exclude<R, I>>I, function (type parameter) S in <I, S>(key: Context.Key<I, S>, service: NoInfer<S>): <A, E, R>(self: Stream<A, E, R>) => Stream<A, E, Exclude<R, I>>S>(
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>(key: Context.Key<I, S>, service: NoInfer<S>): <A, E, R>(self: Stream<A, E, R>) => Stream<A, E, Exclude<R, I>>I, function (type parameter) S in <I, S>(key: Context.Key<I, S>, service: NoInfer<S>): <A, E, R>(self: Stream<A, E, R>) => Stream<A, E, Exclude<R, I>>S>,
service: NoInfer<S>service: 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>(key: Context.Key<I, S>, service: NoInfer<S>): <A, E, R>(self: Stream<A, E, R>) => Stream<A, E, Exclude<R, I>>S>
): <function (type parameter) A in <A, E, R>(self: Stream<A, E, R>): Stream<A, E, Exclude<R, I>>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>): Stream<A, E, Exclude<R, I>>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>): Stream<A, E, Exclude<R, I>>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, Exclude<R, I>>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>): Stream<A, E, Exclude<R, I>>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>): Stream<A, E, Exclude<R, I>>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, Exclude<R, I>>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>): Stream<A, E, Exclude<R, I>>E, 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, Exclude<R, I>>R, function (type parameter) I in <I, S>(key: Context.Key<I, S>, service: NoInfer<S>): <A, E, R>(self: Stream<A, E, R>) => Stream<A, E, Exclude<R, I>>I>>
<function (type parameter) A in <A, E, R, I, S>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>A, function (type parameter) E in <A, E, R, I, S>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>E, function (type parameter) R in <A, E, R, I, S>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>R, function (type parameter) I in <A, E, R, I, S>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>I, function (type parameter) S in <A, E, R, I, S>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>S>(
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>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>A, function (type parameter) E in <A, E, R, I, S>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>E, function (type parameter) R in <A, E, R, I, S>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>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>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>I, function (type parameter) S in <A, E, R, I, S>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>S>,
service: NoInfer<S>service: 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>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>S>
): 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>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>A, function (type parameter) E in <A, E, R, I, S>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>E, 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>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>R, function (type parameter) I in <A, E, R, I, S>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>I>>
} = import dualdual(3, <function (type parameter) A in <A, E, R, I, S>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>A, function (type parameter) E in <A, E, R, I, S>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>E, function (type parameter) R in <A, E, R, I, S>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>R, function (type parameter) I in <A, E, R, I, S>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>I, function (type parameter) S in <A, E, R, I, S>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>S>(
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>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>A, function (type parameter) E in <A, E, R, I, S>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>E, function (type parameter) R in <A, E, R, I, S>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>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>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>I, function (type parameter) S in <A, E, R, I, S>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>S>,
service: NoInfer<S>service: 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>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>S>
): 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>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>A, function (type parameter) E in <A, E, R, I, S>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>E, 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>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>R, function (type parameter) I in <A, E, R, I, S>(self: Stream<A, E, R>, key: Context.Key<I, S>, service: NoInfer<S>): Stream<A, E, Exclude<R, I>>I>> => 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.provideService(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: NoInfer<S>service)))