<A, E2, R2>(
predicate: (
a: NoInfer<A>,
index: number
) => Effect.Effect<boolean, E2, R2>
): <E, R>(self: Stream<A, E, R>) => Stream<A, E2 | E, R2 | R>
<A, E, R, E2, R2>(
self: Stream<A, E, R>,
predicate: (
a: NoInfer<A>,
index: number
) => Effect.Effect<boolean, E2, R2>
): Stream<A, E | E2, R | R2>Drops all elements of the stream until the specified effectful predicate
evaluates to true.
When to use
Use when dropping the leading prefix requires an Effect or service and the first matching element should also be dropped.
Example (Dropping until an effectful predicate matches)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const result = yield* Stream.range(1, 5).pipe(
Stream.dropUntilEffect((n) => Effect.succeed(n % 3 === 0)),
Stream.runCollect
)
yield* Console.log(result)
})
Effect.runPromise(program)
// Output: [ 4, 5 ]filtering
Source effect/Stream.ts:676819 lines
export const const dropUntilEffect: {
<A, E2, R2>(
predicate: (
a: NoInfer<A>,
index: number
) => Effect.Effect<boolean, E2, R2>
): <E, R>(
self: Stream<A, E, R>
) => Stream<A, E2 | E, R2 | R>
<A, E, R, E2, R2>(
self: Stream<A, E, R>,
predicate: (
a: NoInfer<A>,
index: number
) => Effect.Effect<boolean, E2, R2>
): Stream<A, E | E2, R | R2>
}
Drops all elements of the stream until the specified effectful predicate
evaluates to true.
When to use
Use when dropping the leading prefix requires an Effect or service and the
first matching element should also be dropped.
Example (Dropping until an effectful predicate matches)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const result = yield* Stream.range(1, 5).pipe(
Stream.dropUntilEffect((n) => Effect.succeed(n % 3 === 0)),
Stream.runCollect
)
yield* Console.log(result)
})
Effect.runPromise(program)
// Output: [ 4, 5 ]
dropUntilEffect: {
<function (type parameter) A in <A, E2, R2>(predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): <E, R>(self: Stream<A, E, R>) => Stream<A, E2 | E, R2 | R>A, function (type parameter) E2 in <A, E2, R2>(predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): <E, R>(self: Stream<A, E, R>) => Stream<A, E2 | E, R2 | R>E2, function (type parameter) R2 in <A, E2, R2>(predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): <E, R>(self: Stream<A, E, R>) => Stream<A, E2 | E, R2 | R>R2>(
predicate: (
a: NoInfer<A>,
index: number
) => Effect.Effect<boolean, E2, R2>
a: NoInfer<A>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, E2, R2>(predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): <E, R>(self: Stream<A, E, R>) => Stream<A, E2 | E, R2 | R>A>, index: numberindex: number) => import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<boolean, function (type parameter) E2 in <A, E2, R2>(predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): <E, R>(self: Stream<A, E, R>) => Stream<A, E2 | E, R2 | R>E2, function (type parameter) R2 in <A, E2, R2>(predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): <E, R>(self: Stream<A, E, R>) => Stream<A, E2 | E, R2 | R>R2>
): <function (type parameter) E in <E, R>(self: Stream<A, E, R>): Stream<A, E2 | E, R2 | R>E, function (type parameter) R in <E, R>(self: Stream<A, E, R>): Stream<A, E2 | E, R2 | 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, E2, R2>(predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): <E, R>(self: Stream<A, E, R>) => Stream<A, E2 | E, R2 | R>A, function (type parameter) E in <E, R>(self: Stream<A, E, R>): Stream<A, E2 | E, R2 | R>E, function (type parameter) R in <E, R>(self: Stream<A, E, R>): Stream<A, E2 | E, R2 | 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, E2, R2>(predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): <E, R>(self: Stream<A, E, R>) => Stream<A, E2 | E, R2 | R>A, function (type parameter) E2 in <A, E2, R2>(predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): <E, R>(self: Stream<A, E, R>) => Stream<A, E2 | E, R2 | R>E2 | function (type parameter) E in <E, R>(self: Stream<A, E, R>): Stream<A, E2 | E, R2 | R>E, function (type parameter) R2 in <A, E2, R2>(predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): <E, R>(self: Stream<A, E, R>) => Stream<A, E2 | E, R2 | R>R2 | function (type parameter) R in <E, R>(self: Stream<A, E, R>): Stream<A, E2 | E, R2 | R>R>
<function (type parameter) A in <A, E, R, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>A, function (type parameter) E in <A, E, R, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>E, function (type parameter) R in <A, E, R, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>R, function (type parameter) E2 in <A, E, R, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>E2, function (type parameter) R2 in <A, E, R, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>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, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>A, function (type parameter) E in <A, E, R, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>E, function (type parameter) R in <A, E, R, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>R>,
predicate: (
a: NoInfer<A>,
index: number
) => Effect.Effect<boolean, E2, R2>
a: NoInfer<A>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, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>A>, index: numberindex: number) => import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<boolean, function (type parameter) E2 in <A, E, R, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>E2, function (type parameter) R2 in <A, E, R, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>R2>
): 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, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>A, function (type parameter) E in <A, E, R, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>E | function (type parameter) E2 in <A, E, R, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>E2, function (type parameter) R in <A, E, R, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>R | function (type parameter) R2 in <A, E, R, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>R2>
} = import dualdual(2, <function (type parameter) A in <A, E, R, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>A, function (type parameter) E in <A, E, R, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>E, function (type parameter) R in <A, E, R, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>R, function (type parameter) E2 in <A, E, R, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>E2, function (type parameter) R2 in <A, E, R, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>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, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>A, function (type parameter) E in <A, E, R, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>E, function (type parameter) R in <A, E, R, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>R>,
predicate: (
a: NoInfer<A>,
index: number
) => Effect.Effect<boolean, E2, R2>
a: NoInfer<A>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, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>A>, index: numberindex: number) => import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<boolean, function (type parameter) E2 in <A, E, R, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>E2, function (type parameter) R2 in <A, E, R, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>R2>
): 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, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>A, function (type parameter) E in <A, E, R, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>E | function (type parameter) E2 in <A, E, R, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>E2, function (type parameter) R in <A, E, R, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>R | function (type parameter) R2 in <A, E, R, E2, R2>(self: Stream<A, E, R>, predicate: (a: NoInfer<A>, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>R2> =>
const drop: {
(n: number): <A, E, R>(
self: Stream<A, E, R>
) => Stream<A, E, R>
<A, E, R>(
self: Stream<A, E, R>,
n: number
): Stream<A, E, R>
}
const dropWhileEffect: {
<A, E2, R2>(
predicate: (
a: NoInfer<A>,
index: number
) => Effect.Effect<boolean, E2, R2>
): <E, R>(
self: Stream<A, E, R>
) => Stream<A, E2 | E, R2 | R>
<A, E, R, E2, R2>(
self: Stream<A, E, R>,
predicate: (
a: A,
index: number
) => Effect.Effect<boolean, E2, R2>
): Stream<A, 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, i: numberi) => import EffectEffect.map(predicate: (
a: NoInfer<A>,
index: number
) => Effect.Effect<boolean, E2, R2>
a: Aa, i: numberi), (b: anyb) => !b: anyb)
),
1
))