<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>Drops elements while the specified effectful predicate evaluates to true.
Example (Effectfully dropping while a predicate holds)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const result = yield* Stream.make(1, 2, 3, 4, 5).pipe(
Stream.dropWhileEffect((n) => Effect.succeed(n < 3)),
Stream.runCollect
)
yield* Console.log(result)
})
Effect.runPromise(program)
// Output: [ 3, 4, 5 ]filtering
Source effect/Stream.ts:689431 lines
export const 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>
}
Drops elements while the specified effectful predicate evaluates to true.
Example (Effectfully dropping while a predicate holds)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const result = yield* Stream.make(1, 2, 3, 4, 5).pipe(
Stream.dropWhileEffect((n) => Effect.succeed(n < 3)),
Stream.runCollect
)
yield* Console.log(result)
})
Effect.runPromise(program)
// Output: [ 3, 4, 5 ]
dropWhileEffect: {
<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.interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<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: 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: 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: 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: 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: 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: 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: 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: A, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>R>,
predicate: (
a: A,
index: number
) => Effect.Effect<boolean, E2, R2>
a: Aa: function (type parameter) A in <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>A, index: numberindex: number) => import EffectEffect.interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<boolean, function (type parameter) E2 in <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>E2, function (type parameter) R2 in <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>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: 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: 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: 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: 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: A, index: number) => Effect.Effect<boolean, E2, R2>): Stream<A, E | E2, R | R2>R2>
} = dual<(...args: Array<any>) => any, <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>>(arity: 2, body: <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>): ((...args: Array<any>) => any) & (<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>) (+1 overload)Creates a function that can be called in data-first style or data-last
(pipe-friendly) style.
When to use
Use to expose one implementation through both direct and pipe-friendly
call styles.
Details
Pass either the arity of the uncurried function or a predicate that decides
whether the current call is data-first. Arity is the common case. Use a
predicate when optional arguments make arity ambiguous.
Example (Selecting data-first or data-last style by arity)
import { Function, pipe } from "effect"
const sum = Function.dual<
(that: number) => (self: number) => number,
(self: number, that: number) => number
>(2, (self, that) => self + that)
console.log(sum(2, 3)) // 5
console.log(pipe(2, sum(3))) // 5
Example (Defining overloads with call signatures)
import { Function, pipe } from "effect"
const sum: {
(that: number): (self: number) => number
(self: number, that: number): number
} = Function.dual(2, (self: number, that: number): number => self + that)
console.log(sum(2, 3)) // 5
console.log(pipe(2, sum(3))) // 5
Example (Selecting data-first or data-last style with a predicate)
import { Function, pipe } from "effect"
const sum = Function.dual<
(that: number) => (self: number) => number,
(self: number, that: number) => number
>(
(args) => args.length === 2,
(self, that) => self + that
)
console.log(sum(2, 3)) // 5
console.log(pipe(2, sum(3))) // 5
dual(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.interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<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 transformPull: <
A,
E,
R,
B,
E2,
R2,
EX,
RX
>(
self: Stream<A, E, R>,
f: (
pull: Pull.Pull<
Arr.NonEmptyReadonlyArray<A>,
E,
void
>,
scope: Scope.Scope
) => Effect.Effect<
Pull.Pull<
Arr.NonEmptyReadonlyArray<B>,
E2,
void,
R2
>,
EX,
RX
>
) => Stream<
B,
EX | Pull.ExcludeDone<E2>,
R | R2 | RX
>
Derives a stream by transforming its pull effect.
Example (Transforming a pull effect)
import { Console, Effect, Stream } from "effect"
const stream = Stream.make(1, 2, 3)
const transformed = Stream.transformPull(stream, (pull) => Effect.succeed(pull))
const program = Effect.gen(function*() {
const values = yield* Stream.runCollect(transformed)
yield* Console.log(values)
})
Effect.runPromise(program)
// Output: [ 1, 2, 3 ]
transformPull(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; <…;
}
pull: Pull.Pull<
readonly [A, ...A[]],
E,
void,
never
>
(parameter) pull: {
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;
}
_scope: Scope.Scope(parameter) _scope: {
strategy: "sequential" | "parallel";
state: State.Open | State.Closed | State.Empty;
}
import EffectEffect.const sync: <A>(
thunk: LazyArg<A>
) => Effect<A>
Creates an Effect that represents a synchronous side-effectful computation.
When to use
Use when you need to wrap a synchronous side-effectful operation that is not
expected to throw.
Details
The provided function is evaluated lazily when the effect runs.
Gotchas
The function must not throw. If it throws, the thrown value is treated as a
defect, not as a typed failure. Use try when throwing is expected.
Example (Capturing synchronous logging in an Effect)
import { Effect } from "effect"
const log = (message: string) =>
Effect.sync(() => {
console.log(message) // side effect
})
// ┌─── Effect<void, never, never>
// ▼
const program = log("Hello, World!")
sync(() => {
let let dropping: booleandropping = true
let let index: numberindex = 0
const const filtered: Pull.Pull<
Arr.NonEmptyReadonlyArray<A>,
E | E2,
void,
R2
>
const filtered: {
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 PullPull.interface Pull<out A, out E = never, out Done = void, out R = never>An effectful pull step that either produces a value, fails with E, or
signals completion with Cause.Done<Done>.
When to use
Use to model one low-level pull step when a consumer repeatedly evaluates an
effect that may emit a value, fail normally, or signal normal completion
through Cause.Done.
Details
Pull represents completion in the error channel so low-level stream
consumers can distinguish ordinary failures from end-of-input and carry a
leftover value when needed.
Pull<import ArrArr.type NonEmptyReadonlyArray<A> = readonly [
A,
...A[]
]
A readonly array guaranteed to have at least one element.
When to use
Use when non-emptiness must be tracked at the type level while preventing mutation.
Many Array module functions accept or return this type.
Example (Typing a non-empty array)
import type { Array } from "effect"
const nonEmpty: Array.NonEmptyReadonlyArray<number> = [1, 2, 3]
const head: number = nonEmpty[0] // guaranteed to exist
NonEmptyReadonlyArray<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, void, 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 EffectEffect.const gen: {
<Eff extends Effect<any, any, any>, AEff>(
f: () => Generator<Eff, AEff, never>
): Effect<
AEff,
[Eff] extends [never]
? never
: [Eff] extends [
Effect<infer _A, infer E, infer _R>
]
? E
: never,
[Eff] extends [never]
? never
: [Eff] extends [
Effect<infer _A, infer _E, infer R>
]
? R
: never
>
<Self, Eff extends Effect<any, any, any>, AEff>(
options: { readonly self: Self },
f: (this: Self) => Generator<Eff, AEff, never>
): Effect<
AEff,
[Eff] extends [never]
? never
: [Eff] extends [
Effect<infer _A, infer E, infer _R>
]
? E
: never,
[Eff] extends [never]
? never
: [Eff] extends [
Effect<infer _A, infer _E, infer R>
]
? R
: never
>
}
const arr: readonly [A, ...A[]]const arr: {
0: A;
length: number;
toString: () => string;
toLocaleString: { (): string; (locales: string | string[], options?: Intl.NumberFormatOptions & Intl.DateTimeFormatOptions): string };
concat: { (...items: Array<ConcatArray<A>>): Array<A>; (...items: Array<A | ConcatArray<A>>): Array<A> };
join: (separator?: string) => string;
slice: (start?: number, end?: number) => Array<A>;
indexOf: (searchElement: A, fromIndex?: number) => number;
lastIndexOf: (searchElement: A, fromIndex?: number) => number;
every: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): this is readonly S[]; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): boolean };
some: (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any) => boolean;
forEach: (callbackfn: (value: A, index: number, array: ReadonlyArray<A>) => void, thisArg?: any) => void;
map: (callbackfn: (value: A, index: number, array: ReadonlyArray<A>) => U, thisArg?: any) => Array<U>;
filter: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): Array<S>; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): Array<A> };
reduce: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A, initialValue: A): A; (callbac…;
reduceRight: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A, initialValue: A): A; (callbac…;
find: { (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => unknown, thisArg?: any): A | undefined };
findIndex: (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => unknown, thisArg?: any) => number;
entries: () => ArrayIterator<[number, A]>;
keys: () => ArrayIterator<number>;
values: () => ArrayIterator<A>;
includes: (searchElement: A, fromIndex?: number) => boolean;
flatMap: (callback: (this: This, value: A, index: number, array: Array<A>) => U | ReadonlyArray<U>, thisArg?: This | undefined) => Array<U>;
flat: (this: A, depth?: D | undefined) => Array<FlatArray<A, D>>;
at: (index: number) => A | undefined;
findLast: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): A | undefined };
findLastIndex: (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any) => number;
toReversed: () => Array<A>;
toSorted: (compareFn?: ((a: A, b: A) => number) | undefined) => Array<A>;
toSpliced: { (start: number, deleteCount: number, ...items: Array<A>): Array<A>; (start: number, deleteCount?: number): Array<A> };
with: (index: number, value: A) => Array<A>;
}
pull: Pull.Pull<
readonly [A, ...A[]],
E,
void,
never
>
(parameter) pull: {
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;
}
let i: numberi = 0; let i: numberi < const arr: readonly [A, ...A[]]const arr: {
0: A;
length: number;
toString: () => string;
toLocaleString: { (): string; (locales: string | string[], options?: Intl.NumberFormatOptions & Intl.DateTimeFormatOptions): string };
concat: { (...items: Array<ConcatArray<A>>): Array<A>; (...items: Array<A | ConcatArray<A>>): Array<A> };
join: (separator?: string) => string;
slice: (start?: number, end?: number) => Array<A>;
indexOf: (searchElement: A, fromIndex?: number) => number;
lastIndexOf: (searchElement: A, fromIndex?: number) => number;
every: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): this is readonly S[]; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): boolean };
some: (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any) => boolean;
forEach: (callbackfn: (value: A, index: number, array: ReadonlyArray<A>) => void, thisArg?: any) => void;
map: (callbackfn: (value: A, index: number, array: ReadonlyArray<A>) => U, thisArg?: any) => Array<U>;
filter: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): Array<S>; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): Array<A> };
reduce: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A, initialValue: A): A; (callbac…;
reduceRight: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A, initialValue: A): A; (callbac…;
find: { (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => unknown, thisArg?: any): A | undefined };
findIndex: (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => unknown, thisArg?: any) => number;
entries: () => ArrayIterator<[number, A]>;
keys: () => ArrayIterator<number>;
values: () => ArrayIterator<A>;
includes: (searchElement: A, fromIndex?: number) => boolean;
flatMap: (callback: (this: This, value: A, index: number, array: Array<A>) => U | ReadonlyArray<U>, thisArg?: This | undefined) => Array<U>;
flat: (this: A, depth?: D | undefined) => Array<FlatArray<A, D>>;
at: (index: number) => A | undefined;
findLast: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): A | undefined };
findLastIndex: (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any) => number;
toReversed: () => Array<A>;
toSorted: (compareFn?: ((a: A, b: A) => number) | undefined) => Array<A>;
toSpliced: { (start: number, deleteCount: number, ...items: Array<A>): Array<A>; (start: number, deleteCount?: number): Array<A> };
with: (index: number, value: A) => Array<A>;
}
length: numberlength; let i: numberi++) {
const const drop: booleandrop = yield* predicate: (
a: NoInfer<A>,
index: number
) => Effect.Effect<boolean, E2, R2>
const arr: readonly [A, ...A[]]const arr: {
0: A;
length: number;
toString: () => string;
toLocaleString: { (): string; (locales: string | string[], options?: Intl.NumberFormatOptions & Intl.DateTimeFormatOptions): string };
concat: { (...items: Array<ConcatArray<A>>): Array<A>; (...items: Array<A | ConcatArray<A>>): Array<A> };
join: (separator?: string) => string;
slice: (start?: number, end?: number) => Array<A>;
indexOf: (searchElement: A, fromIndex?: number) => number;
lastIndexOf: (searchElement: A, fromIndex?: number) => number;
every: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): this is readonly S[]; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): boolean };
some: (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any) => boolean;
forEach: (callbackfn: (value: A, index: number, array: ReadonlyArray<A>) => void, thisArg?: any) => void;
map: (callbackfn: (value: A, index: number, array: ReadonlyArray<A>) => U, thisArg?: any) => Array<U>;
filter: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): Array<S>; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): Array<A> };
reduce: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A, initialValue: A): A; (callbac…;
reduceRight: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A, initialValue: A): A; (callbac…;
find: { (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => unknown, thisArg?: any): A | undefined };
findIndex: (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => unknown, thisArg?: any) => number;
entries: () => ArrayIterator<[number, A]>;
keys: () => ArrayIterator<number>;
values: () => ArrayIterator<A>;
includes: (searchElement: A, fromIndex?: number) => boolean;
flatMap: (callback: (this: This, value: A, index: number, array: Array<A>) => U | ReadonlyArray<U>, thisArg?: This | undefined) => Array<U>;
flat: (this: A, depth?: D | undefined) => Array<FlatArray<A, D>>;
at: (index: number) => A | undefined;
findLast: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): A | undefined };
findLastIndex: (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any) => number;
toReversed: () => Array<A>;
toSorted: (compareFn?: ((a: A, b: A) => number) | undefined) => Array<A>;
toSpliced: { (start: number, deleteCount: number, ...items: Array<A>): Array<A>; (start: number, deleteCount?: number): Array<A> };
with: (index: number, value: A) => Array<A>;
}
let i: numberi], let index: numberindex++)
if (const drop: booleandrop) continue
let dropping: booleandropping = false
return const arr: readonly [A, ...A[]]const arr: {
0: A;
length: number;
toString: () => string;
toLocaleString: { (): string; (locales: string | string[], options?: Intl.NumberFormatOptions & Intl.DateTimeFormatOptions): string };
concat: { (...items: Array<ConcatArray<A>>): Array<A>; (...items: Array<A | ConcatArray<A>>): Array<A> };
join: (separator?: string) => string;
slice: (start?: number, end?: number) => Array<A>;
indexOf: (searchElement: A, fromIndex?: number) => number;
lastIndexOf: (searchElement: A, fromIndex?: number) => number;
every: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): this is readonly S[]; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): boolean };
some: (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any) => boolean;
forEach: (callbackfn: (value: A, index: number, array: ReadonlyArray<A>) => void, thisArg?: any) => void;
map: (callbackfn: (value: A, index: number, array: ReadonlyArray<A>) => U, thisArg?: any) => Array<U>;
filter: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): Array<S>; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): Array<A> };
reduce: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A, initialValue: A): A; (callbac…;
reduceRight: { (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A): A; (callbackfn: (previousValue: A, currentValue: A, currentIndex: number, array: ReadonlyArray<A>) => A, initialValue: A): A; (callbac…;
find: { (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => unknown, thisArg?: any): A | undefined };
findIndex: (predicate: (value: A, index: number, obj: ReadonlyArray<A>) => unknown, thisArg?: any) => number;
entries: () => ArrayIterator<[number, A]>;
keys: () => ArrayIterator<number>;
values: () => ArrayIterator<A>;
includes: (searchElement: A, fromIndex?: number) => boolean;
flatMap: (callback: (this: This, value: A, index: number, array: Array<A>) => U | ReadonlyArray<U>, thisArg?: This | undefined) => Array<U>;
flat: (this: A, depth?: D | undefined) => Array<FlatArray<A, D>>;
at: (index: number) => A | undefined;
findLast: { (predicate: (value: A, index: number, array: ReadonlyArray<A>) => value is S, thisArg?: any): S | undefined; (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any): A | undefined };
findLastIndex: (predicate: (value: A, index: number, array: ReadonlyArray<A>) => unknown, thisArg?: any) => number;
toReversed: () => Array<A>;
toSorted: (compareFn?: ((a: A, b: A) => number) | undefined) => Array<A>;
toSpliced: { (start: number, deleteCount: number, ...items: Array<A>): Array<A>; (start: number, deleteCount?: number): Array<A> };
with: (index: number, value: A) => Array<A>;
}
ReadonlyArray<A>.slice(start?: number, end?: number): A[]Returns a section of an array.
slice(let i: numberi) as import ArrArr.type NonEmptyArray<A> = [A, ...A[]]A mutable array guaranteed to have at least one element.
When to use
Use when mutation is acceptable and non-emptiness must be tracked at the type
level.
Details
This is the mutable counterpart of
NonEmptyReadonlyArray
. Most Array
module functions return NonEmptyArray when the result is guaranteed
non-empty.
Example (Typing a mutable non-empty array)
import type { Array } from "effect"
const nonEmpty: Array.NonEmptyArray<number> = [1, 2, 3]
nonEmpty.push(4)
NonEmptyArray<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>
}
}
})
return import EffectEffect.const suspend: <A, E, R>(
effect: LazyArg<Effect<A, E, R>>
) => Effect<A, E, R>
Creates an Effect lazily, delaying construction until it is needed.
When to use
Use when you need to defer the evaluation of an effect until it is required.
Details
suspend takes a thunk that represents an effect and delays creating it
until the suspended effect is evaluated. This is useful for optimizing
expensive computations, managing circular dependencies such as recursive
functions, and helping TypeScript unify return types when branches construct
different effects. Any side effects or scoped captures inside the thunk are
re-executed on each invocation.
Example (Lazily evaluating side effects)
import { Effect } from "effect"
let i = 0
const bad = Effect.succeed(i++)
const good = Effect.suspend(() => Effect.succeed(i++))
console.log(Effect.runSync(bad)) // Output: 0
console.log(Effect.runSync(bad)) // Output: 0
console.log(Effect.runSync(good)) // Output: 1
console.log(Effect.runSync(good)) // Output: 2
Example (Suspending recursive Fibonacci evaluation)
import { Effect } from "effect"
const blowsUp = (n: number): Effect.Effect<number> =>
n < 2
? Effect.succeed(1)
: Effect.zipWith(blowsUp(n - 1), blowsUp(n - 2), (a, b) => a + b)
// console.log(Effect.runSync(blowsUp(32)))
// crash: JavaScript heap out of memory
const allGood = (n: number): Effect.Effect<number> =>
n < 2
? Effect.succeed(1)
: Effect.zipWith(
Effect.suspend(() => allGood(n - 1)),
Effect.suspend(() => allGood(n - 2)),
(a, b) => a + b
)
console.log(Effect.runSync(allGood(32)))
// Output: 3524578
Example (Helping TypeScript infer recursive effect types)
import { Effect } from "effect"
// Without suspend, TypeScript may struggle with type inference.
// Inferred type:
// (a: number, b: number) =>
// Effect<never, Error, never> | Effect<number, never, never>
const withoutSuspend = (a: number, b: number) =>
b === 0
? Effect.fail(new Error("Cannot divide by zero"))
: Effect.succeed(a / b)
// Using suspend to unify return types.
// Inferred type:
// (a: number, b: number) => Effect<number, Error, never>
const withSuspend = (a: number, b: number) =>
Effect.suspend(() =>
b === 0
? Effect.fail(new Error("Cannot divide by zero"))
: Effect.succeed(a / b)
)
suspend((): import PullPull.interface Pull<out A, out E = never, out Done = void, out R = never>An effectful pull step that either produces a value, fails with E, or
signals completion with Cause.Done<Done>.
When to use
Use to model one low-level pull step when a consumer repeatedly evaluates an
effect that may emit a value, fail normally, or signal normal completion
through Cause.Done.
Details
Pull represents completion in the error channel so low-level stream
consumers can distinguish ordinary failures from end-of-input and carry a
leftover value when needed.
Pull<import ArrArr.type NonEmptyReadonlyArray<A> = readonly [
A,
...A[]
]
A readonly array guaranteed to have at least one element.
When to use
Use when non-emptiness must be tracked at the type level while preventing mutation.
Many Array module functions accept or return this type.
Example (Typing a non-empty array)
import type { Array } from "effect"
const nonEmpty: Array.NonEmptyReadonlyArray<number> = [1, 2, 3]
const head: number = nonEmpty[0] // guaranteed to exist
NonEmptyReadonlyArray<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, void, 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> =>
let dropping: booleandropping ? const filtered: Pull.Pull<
Arr.NonEmptyReadonlyArray<A>,
E | E2,
void,
R2
>
const filtered: {
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;
}
pull: Pull.Pull<
readonly [A, ...A[]],
E,
void,
never
>
(parameter) pull: {
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
toString: () => string;
toJSON: () => unknown;
}
Referenced by 1 symbols