<N extends string, A, B, E2, R2>(
tag: Exclude<N, keyof A>,
f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>,
options?: {
readonly concurrency?: number | "unbounded" | undefined
readonly bufferSize?: number | undefined
readonly unordered?: boolean | undefined
}
): <E, R>(
self: Stream<A, E, R>
) => Stream<
{ [K in keyof A | N]: K extends keyof A ? A[K] : B },
E | E2,
R | R2
>
<A, E, R, N extends string, B, E2, R2>(
self: Stream<A, E, R>,
tag: Exclude<N, keyof A>,
f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>,
options?: {
readonly concurrency?: number | "unbounded" | undefined
readonly bufferSize?: number | undefined
readonly unordered?: boolean | undefined
}
): Stream<
{ [K in keyof A | N]: K extends keyof A ? A[K] : B },
E | E2,
R | R2
>Binds an Effect-produced value into the do-notation record for each stream element.
Example (Binding an effect value)
import { Console, Effect, Stream } from "effect"
const stream = Stream.Do.pipe(
Stream.bind("value", () => Stream.make(1, 2)),
Stream.bindEffect("double", ({ value }) => Effect.succeed(value * 2))
)
const program = Effect.gen(function*() {
const result = yield* Stream.runCollect(stream)
yield* Console.log(result)
})
Effect.runPromise(program)
// [{ value: 1, double: 2 }, { value: 2, double: 4 }]do notation
Source effect/Stream.ts:1050131 lines
export const const bindEffect: {
<N extends string, A, B, E2, R2>(
tag: Exclude<N, keyof A>,
f: (
_: NoInfer<A>
) => Effect.Effect<B, E2, R2>,
options?: {
readonly concurrency?:
| number
| "unbounded"
| undefined
readonly bufferSize?: number | undefined
readonly unordered?: boolean | undefined
}
): <E, R>(
self: Stream<A, E, R>
) => Stream<
{
[K in keyof A | N]: K extends keyof A
? A[K]
: B
},
E | E2,
R | R2
>
<A, E, R, N extends string, B, E2, R2>(
self: Stream<A, E, R>,
tag: Exclude<N, keyof A>,
f: (
_: NoInfer<A>
) => Effect.Effect<B, E2, R2>,
options?: {
readonly concurrency?:
| number
| "unbounded"
| undefined
readonly bufferSize?: number | undefined
readonly unordered?: boolean | undefined
}
): Stream<
{
[K in keyof A | N]: K extends keyof A
? A[K]
: B
},
E | E2,
R | R2
>
}
Binds an Effect-produced value into the do-notation record for each stream element.
Example (Binding an effect value)
import { Console, Effect, Stream } from "effect"
const stream = Stream.Do.pipe(
Stream.bind("value", () => Stream.make(1, 2)),
Stream.bindEffect("double", ({ value }) => Effect.succeed(value * 2))
)
const program = Effect.gen(function*() {
const result = yield* Stream.runCollect(stream)
yield* Console.log(result)
})
Effect.runPromise(program)
// [{ value: 1, double: 2 }, { value: 2, double: 4 }]
bindEffect: {
<function (type parameter) N in <N extends string, A, B, E2, R2>(tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) A in <N extends string, A, B, E2, R2>(tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) B in <N extends string, A, B, E2, R2>(tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) E2 in <N extends string, A, B, E2, R2>(tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) R2 in <N extends string, A, B, E2, R2>(tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
tag: Exclude<N, keyof A>tag: type Exclude<T, U> = T extends U
? never
: T
Exclude from T those types that are assignable to U
Exclude<function (type parameter) N in <N extends string, A, B, E2, R2>(tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) A in <N extends string, A, B, E2, R2>(tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
f: (
_: NoInfer<A>
) => Effect.Effect<B, E2, R2>
_: NoInfer<A>_: 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 <N extends string, A, B, E2, R2>(tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<function (type parameter) B in <N extends string, A, B, E2, R2>(tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) E2 in <N extends string, A, B, E2, R2>(tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) R2 in <N extends string, A, B, E2, R2>(tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
options: | {
readonly concurrency?:
| number
| "unbounded"
| undefined
readonly bufferSize?: number | undefined
readonly unordered?: boolean | undefined
}
| undefined
concurrency?: number | "unbounded" | undefinedconcurrency?: number | "unbounded" | undefined
readonly bufferSize?: number | undefinedbufferSize?: number | undefined
readonly unordered?: boolean | undefinedunordered?: boolean | undefined
}
): <function (type parameter) E in <E, R>(self: Stream<A, E, R>): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>E, function (type parameter) R in <E, R>(self: Stream<A, E, R>): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>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 <N extends string, A, B, E2, R2>(tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) E in <E, R>(self: Stream<A, E, R>): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>E, function (type parameter) R in <E, R>(self: Stream<A, E, R>): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>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) KK in keyof function (type parameter) A in <N extends string, A, B, E2, R2>(tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) N in <N extends string, A, B, E2, R2>(tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) KK extends keyof function (type parameter) A in <N extends string, A, B, E2, R2>(tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) A in <N extends string, A, B, E2, R2>(tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) KK] : function (type parameter) B in <N extends string, A, B, E2, R2>(tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) E in <E, R>(self: Stream<A, E, R>): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>E | function (type parameter) E2 in <N extends string, A, B, E2, R2>(tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) R in <E, R>(self: Stream<A, E, R>): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>R | function (type parameter) R2 in <N extends string, A, B, E2, R2>(tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): <E, R>(self: Stream<A, E, R>) => Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) A in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) E in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) R in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) N in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) B in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) E2 in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) R2 in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
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, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) E in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) R in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
tag: Exclude<N, keyof A>tag: type Exclude<T, U> = T extends U
? never
: T
Exclude from T those types that are assignable to U
Exclude<function (type parameter) N in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) A in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
f: (
_: NoInfer<A>
) => Effect.Effect<B, E2, R2>
_: NoInfer<A>_: 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, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<function (type parameter) B in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) E2 in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) R2 in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
options: | {
readonly concurrency?:
| number
| "unbounded"
| undefined
readonly bufferSize?: number | undefined
readonly unordered?: boolean | undefined
}
| undefined
concurrency?: number | "unbounded" | undefinedconcurrency?: number | "unbounded" | undefined
readonly bufferSize?: number | undefinedbufferSize?: number | undefined
readonly unordered?: boolean | undefinedunordered?: boolean | undefined
}
): 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) KK in keyof function (type parameter) A in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) N in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) KK extends keyof function (type parameter) A in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) A in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) KK] : function (type parameter) B in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) E in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) E2 in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) R in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) R2 in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
}): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
import dualdual((args: anyargs) => const isStream: (
u: unknown
) => u is Stream<unknown, unknown, unknown>
Checks whether a value is a Stream.
Example (Checking whether a value is a Stream)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const stream = Stream.make(1, 2, 3)
const notStream = { data: [1, 2, 3] }
yield* Console.log(Stream.isStream(stream))
// true
yield* Console.log(Stream.isStream(notStream))
// false
})
Effect.runPromise(program)
isStream(args: anyargs[0]), <function (type parameter) A in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
} | undefined): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) E in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
} | undefined): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) R in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
} | undefined): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) N in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
} | undefined): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) B in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
} | undefined): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) E2 in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
} | undefined): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) R2 in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
} | undefined): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
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, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
} | undefined): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) E in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
} | undefined): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) R in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
} | undefined): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
tag: Exclude<N, keyof A>tag: type Exclude<T, U> = T extends U
? never
: T
Exclude from T those types that are assignable to U
Exclude<function (type parameter) N in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
} | undefined): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) A in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
} | undefined): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
f: (
_: NoInfer<A>
) => Effect.Effect<B, E2, R2>
_: NoInfer<A>_: 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, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
} | undefined): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<function (type parameter) B in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
} | undefined): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) E2 in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
} | undefined): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) R2 in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
} | undefined): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
options: | {
readonly concurrency?:
| number
| "unbounded"
| undefined
readonly bufferSize?: number | undefined
readonly unordered?: boolean | undefined
}
| undefined
concurrency?: number | "unbounded" | undefinedconcurrency?: number | "unbounded" | undefined
readonly bufferSize?: number | undefinedbufferSize?: number | undefined
readonly unordered?: boolean | undefinedunordered?: boolean | undefined
} | undefined
): 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) KK in keyof function (type parameter) A in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
} | undefined): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) N in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
} | undefined): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) KK extends keyof function (type parameter) A in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
} | undefined): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) A in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
} | undefined): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) KK] : function (type parameter) B in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
} | undefined): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) E in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
} | undefined): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) E2 in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
} | undefined): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) R in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
} | undefined): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
function (type parameter) R2 in <A, E, R, N extends string, B, E2, R2>(self: Stream<A, E, R>, tag: Exclude<N, keyof A>, f: (_: NoInfer<A>) => Effect.Effect<B, E2, R2>, options?: {
readonly concurrency?: number | "unbounded" | undefined;
readonly bufferSize?: number | undefined;
readonly unordered?: boolean | undefined;
} | undefined): Stream<{ [K in keyof A | N]: K extends keyof A ? A[K] : B; }, E | E2, R | R2>
const mapEffect: {
<A, A2, E2, R2>(
f: (
a: A,
i: number
) => Effect.Effect<A2, E2, R2>,
options?:
| {
readonly concurrency?:
| number
| "unbounded"
| undefined
readonly unordered?: boolean | undefined
}
| undefined
): <E, R>(
self: Stream<A, E, R>
) => Stream<A2, E2 | E, R2 | R>
<A, E, R, A2, E2, R2>(
self: Stream<A, E, R>,
f: (
a: A,
i: number
) => Effect.Effect<A2, E2, R2>,
options?:
| {
readonly concurrency?:
| number
| "unbounded"
| undefined
readonly unordered?: boolean | undefined
}
| undefined
): Stream<A2, E | E2, R | R2>
}
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; <…;
}
a: Aa) => import EffectEffect.map(f: (
_: NoInfer<A>
) => Effect.Effect<B, E2, R2>
a: Aa), (b: anyb) => ({ ...a: Aa, [tag: Exclude<N, keyof A>tag]: b: anyb } as any)), options: | {
readonly concurrency?:
| number
| "unbounded"
| undefined
readonly bufferSize?: number | undefined
readonly unordered?: boolean | undefined
}
| undefined