<A, B extends A>(refinement: Refinement<NoInfer<A>, B>): <E, R>(
self: Stream<A, E, R>
) => Stream<B, E, R>
<A>(predicate: Predicate<NoInfer<A>>): <E, R>(
self: Stream<A, E, R>
) => Stream<A, E, R>
<A, E, R, B extends A>(
self: Stream<A, E, R>,
refinement: Refinement<A, B>
): Stream<B, E, R>
<A, E, R>(self: Stream<A, E, R>, predicate: Predicate<A>): Stream<A, E, R>Filters a stream to the elements that satisfy a predicate.
Example (Filtering stream values)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const stream = Stream.make(1, 2, 3, 4).pipe(
Stream.filter((n) => n % 2 === 0)
)
const values = yield* Stream.runCollect(stream)
yield* Console.log(values)
})
Effect.runPromise(program)
// Output: [ 2, 4 ]export const const filter: {
<A, B extends A>(
refinement: Refinement<NoInfer<A>, B>
): <E, R>(
self: Stream<A, E, R>
) => Stream<B, E, R>
<A>(predicate: Predicate<NoInfer<A>>): <E, R>(
self: Stream<A, E, R>
) => Stream<A, E, R>
<A, E, R, B extends A>(
self: Stream<A, E, R>,
refinement: Refinement<A, B>
): Stream<B, E, R>
<A, E, R>(
self: Stream<A, E, R>,
predicate: Predicate<A>
): Stream<A, E, R>
}
Filters a stream to the elements that satisfy a predicate.
Example (Filtering stream values)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const stream = Stream.make(1, 2, 3, 4).pipe(
Stream.filter((n) => n % 2 === 0)
)
const values = yield* Stream.runCollect(stream)
yield* Console.log(values)
})
Effect.runPromise(program)
// Output: [ 2, 4 ]
filter: {
<function (type parameter) A in <A, B extends A>(refinement: Refinement<NoInfer<A>, B>): <E, R>(self: Stream<A, E, R>) => Stream<B, E, R>A, function (type parameter) B in <A, B extends A>(refinement: Refinement<NoInfer<A>, B>): <E, R>(self: Stream<A, E, R>) => Stream<B, E, R>B extends function (type parameter) A in <A, B extends A>(refinement: Refinement<NoInfer<A>, B>): <E, R>(self: Stream<A, E, R>) => Stream<B, E, R>A>(refinement: Refinement<NoInfer<A>, B>refinement: import RefinementRefinement<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) A in <A, B extends A>(refinement: Refinement<NoInfer<A>, B>): <E, R>(self: Stream<A, E, R>) => Stream<B, E, R>A>, function (type parameter) B in <A, B extends A>(refinement: Refinement<NoInfer<A>, B>): <E, R>(self: Stream<A, E, R>) => Stream<B, E, R>B>): <function (type parameter) E in <E, R>(self: Stream<A, E, R>): Stream<B, E, R>E, function (type parameter) R in <E, R>(self: Stream<A, E, R>): Stream<B, E, R>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, B extends A>(refinement: Refinement<NoInfer<A>, B>): <E, R>(self: Stream<A, E, R>) => Stream<B, E, R>A, function (type parameter) E in <E, R>(self: Stream<A, E, R>): Stream<B, E, R>E, function (type parameter) R in <E, R>(self: Stream<A, E, R>): Stream<B, E, R>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) B in <A, B extends A>(refinement: Refinement<NoInfer<A>, B>): <E, R>(self: Stream<A, E, R>) => Stream<B, E, R>B, function (type parameter) E in <E, R>(self: Stream<A, E, R>): Stream<B, E, R>E, function (type parameter) R in <E, R>(self: Stream<A, E, R>): Stream<B, E, R>R>
<function (type parameter) A in <A>(predicate: Predicate<NoInfer<A>>): <E, R>(self: Stream<A, E, R>) => Stream<A, E, R>A>(predicate: Predicate<NoInfer<A>>predicate: import PredicatePredicate<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) A in <A>(predicate: Predicate<NoInfer<A>>): <E, R>(self: Stream<A, E, R>) => Stream<A, E, R>A>>): <function (type parameter) E in <E, R>(self: Stream<A, E, R>): Stream<A, E, R>E, function (type parameter) R in <E, R>(self: Stream<A, E, R>): Stream<A, E, R>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>(predicate: Predicate<NoInfer<A>>): <E, R>(self: Stream<A, E, R>) => Stream<A, E, R>A, function (type parameter) E in <E, R>(self: Stream<A, E, R>): Stream<A, E, R>E, function (type parameter) R in <E, R>(self: Stream<A, E, R>): Stream<A, E, R>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>(predicate: Predicate<NoInfer<A>>): <E, R>(self: Stream<A, E, R>) => Stream<A, E, R>A, function (type parameter) E in <E, R>(self: Stream<A, E, R>): Stream<A, E, R>E, function (type parameter) R in <E, R>(self: Stream<A, E, R>): Stream<A, E, R>R>
<function (type parameter) A in <A, E, R, B extends A>(self: Stream<A, E, R>, refinement: Refinement<A, B>): Stream<B, E, R>A, function (type parameter) E in <A, E, R, B extends A>(self: Stream<A, E, R>, refinement: Refinement<A, B>): Stream<B, E, R>E, function (type parameter) R in <A, E, R, B extends A>(self: Stream<A, E, R>, refinement: Refinement<A, B>): Stream<B, E, R>R, function (type parameter) B in <A, E, R, B extends A>(self: Stream<A, E, R>, refinement: Refinement<A, B>): Stream<B, E, R>B extends function (type parameter) A in <A, E, R, B extends A>(self: Stream<A, E, R>, refinement: Refinement<A, B>): Stream<B, E, R>A>(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, B extends A>(self: Stream<A, E, R>, refinement: Refinement<A, B>): Stream<B, E, R>A, function (type parameter) E in <A, E, R, B extends A>(self: Stream<A, E, R>, refinement: Refinement<A, B>): Stream<B, E, R>E, function (type parameter) R in <A, E, R, B extends A>(self: Stream<A, E, R>, refinement: Refinement<A, B>): Stream<B, E, R>R>, refinement: Refinement<A, B>refinement: import RefinementRefinement<function (type parameter) A in <A, E, R, B extends A>(self: Stream<A, E, R>, refinement: Refinement<A, B>): Stream<B, E, R>A, function (type parameter) B in <A, E, R, B extends A>(self: Stream<A, E, R>, refinement: Refinement<A, B>): Stream<B, E, R>B>): 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) B in <A, E, R, B extends A>(self: Stream<A, E, R>, refinement: Refinement<A, B>): Stream<B, E, R>B, function (type parameter) E in <A, E, R, B extends A>(self: Stream<A, E, R>, refinement: Refinement<A, B>): Stream<B, E, R>E, function (type parameter) R in <A, E, R, B extends A>(self: Stream<A, E, R>, refinement: Refinement<A, B>): Stream<B, E, R>R>
<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>, predicate: Predicate<A>): Stream<A, E, R>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, predicate: Predicate<A>): Stream<A, E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, predicate: Predicate<A>): Stream<A, E, R>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>, predicate: Predicate<A>): Stream<A, E, R>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, predicate: Predicate<A>): Stream<A, E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, predicate: Predicate<A>): Stream<A, E, R>R>,
predicate: Predicate<A>predicate: import PredicatePredicate<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>, predicate: Predicate<A>): Stream<A, E, R>A>
): 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>, predicate: Predicate<A>): Stream<A, E, R>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, predicate: Predicate<A>): Stream<A, E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, predicate: Predicate<A>): Stream<A, E, R>R>
} = import dualdual(
2,
<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>, predicate: Predicate<A>): Stream<A, E, R>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, predicate: Predicate<A>): Stream<A, E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, predicate: Predicate<A>): Stream<A, E, R>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>, predicate: Predicate<A>): Stream<A, E, R>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, predicate: Predicate<A>): Stream<A, E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, predicate: Predicate<A>): Stream<A, E, R>R>,
predicate: Predicate<A>predicate: import PredicatePredicate<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>, predicate: Predicate<A>): Stream<A, E, R>A>
): 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>, predicate: Predicate<A>): Stream<A, E, R>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, predicate: Predicate<A>): Stream<A, E, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, predicate: Predicate<A>): Stream<A, E, R>R> => 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.filterArray(const toChannel: <A, E, R>(
stream: Stream<A, E, R>
) => Channel.Channel<
Arr.NonEmptyReadonlyArray<A>,
E,
void,
unknown,
unknown,
unknown,
R
>
Creates a channel from a stream.
Example (Converting a stream to a channel)
import { Channel, Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const stream = Stream.make(1, 2, 3)
const channel = Stream.toChannel(stream)
const values = yield* Channel.runCollect(channel)
yield* Console.log(values.flat())
})
Effect.runPromise(program)
// Output: [ 1, 2, 3 ]
toChannel(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; <…;
}
predicate: Predicate<A>predicate))
)