<
Arg extends
| Stream<any, any, any>
| { readonly log?: boolean | Severity | undefined }
| undefined
>(
streamOrOptions: Arg,
options?: { readonly log?: boolean | Severity | undefined } | undefined
): [Arg] extends [Stream<infer A, infer _E, infer R>]
? Stream<A, never, R>
: <A, E, R>(self: Stream<A, E, R>) => Stream<A, never, R>Ignores the stream's failure cause, including defects, and ends the stream.
When to use
Use when you need to silently suppress a stream's entire failure cause, including both typed errors and defects, rather than propagate it downstream.
Example (Ignoring stream failure causes)
import { Effect, Stream } from "effect"
Effect.runPromise(Effect.gen(function*() {
const values = yield* Stream.make(1, 2).pipe(
Stream.concat(Stream.die("boom")),
Stream.ignoreCause({ log: false }),
Stream.runCollect
)
yield* Effect.sync(() => console.log(values))
}))
// [ 1, 2 ]export const const ignoreCause: <
Arg extends
| Stream<any, any, any>
| {
readonly log?:
| boolean
| Severity
| undefined
}
| undefined
>(
streamOrOptions: Arg,
options?:
| {
readonly log?:
| boolean
| Severity
| undefined
}
| undefined
) => [Arg] extends [
Stream<infer A, infer _E, infer R>
]
? Stream<A, never, R>
: <A, E, R>(
self: Stream<A, E, R>
) => Stream<A, never, R>
Ignores the stream's failure cause, including defects, and ends the stream.
When to use
Use when you need to silently suppress a stream's entire failure cause,
including both typed errors and defects, rather than propagate it downstream.
Example (Ignoring stream failure causes)
import { Effect, Stream } from "effect"
Effect.runPromise(Effect.gen(function*() {
const values = yield* Stream.make(1, 2).pipe(
Stream.concat(Stream.die("boom")),
Stream.ignoreCause({ log: false }),
Stream.runCollect
)
yield* Effect.sync(() => console.log(values))
}))
// [ 1, 2 ]
ignoreCause: <
function (type parameter) Arg in <Arg extends Stream<any, any, any> | {
readonly log?: boolean | Severity | undefined;
} | undefined>(streamOrOptions: Arg, options?: {
readonly log?: boolean | Severity | undefined;
} | undefined): [Arg] extends [Stream<infer A, infer _E, infer R>] ? Stream<A, never, R> : <A, E, R>(self: Stream<A, E, R>) => Stream<A, never, 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<any, any, any> | {
readonly log?: boolean | Severity | undefinedlog?: boolean | type Severity = "Fatal" | "Error" | "Warn" | "Info" | "Debug" | "Trace"Log levels that represent actual message severities, excluding the All and
None sentinel levels.
When to use
Use when typing emitted log message severities, such as explicit log calls,
current log level references, or error-report severity annotations, where
All and None are not valid values.
Severity | undefined
} | undefined
>(
streamOrOptions: Arg extends Stream<any, any, any> | { readonly log?: boolean | Severity | undefined; } | undefinedstreamOrOptions: function (type parameter) Arg in <Arg extends Stream<any, any, any> | {
readonly log?: boolean | Severity | undefined;
} | undefined>(streamOrOptions: Arg, options?: {
readonly log?: boolean | Severity | undefined;
} | undefined): [Arg] extends [Stream<infer A, infer _E, infer R>] ? Stream<A, never, R> : <A, E, R>(self: Stream<A, E, R>) => Stream<A, never, R>
options: | {
readonly log?:
| boolean
| Severity
| undefined
}
| undefined
log?: boolean | Severity | undefinedlog?: boolean | type Severity = "Fatal" | "Error" | "Warn" | "Info" | "Debug" | "Trace"Log levels that represent actual message severities, excluding the All and
None sentinel levels.
When to use
Use when typing emitted log message severities, such as explicit log calls,
current log level references, or error-report severity annotations, where
All and None are not valid values.
Severity | undefined
} | undefined
) => [function (type parameter) Arg in <Arg extends Stream<any, any, any> | {
readonly log?: boolean | Severity | undefined;
} | undefined>(streamOrOptions: Arg, options?: {
readonly log?: boolean | Severity | undefined;
} | undefined): [Arg] extends [Stream<infer A, infer _E, infer R>] ? Stream<A, never, R> : <A, E, R>(self: Stream<A, E, R>) => Stream<A, never, 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<infer function (type parameter) AA, infer function (type parameter) _E_E, infer function (type parameter) RR>] ? 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) AA, never, function (type parameter) RR>
: <function (type parameter) A in <A, E, R>(self: Stream<A, E, R>): Stream<A, never, R>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>): Stream<A, never, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>): Stream<A, never, R>R>(self: Stream<A, E, R>(parameter) self: {
channel: Channel.Channel<Arr.NonEmptyReadonlyArray<A>, E, void, unknown, unknown, unknown, R>;
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
}
interface Stream<out A, out E = never, out R = never>A Stream<A, E, R> describes a program that can emit many A values, fail
with E, and require R.
Details
Streams are pull-based with backpressure and emit chunks to amortize effect
evaluation. They support monadic composition and error handling similar to
Effect, adapted for multiple values.
Example (Creating and consuming streams)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
yield* Stream.make(1, 2, 3).pipe(
Stream.map((n) => n * 2),
Stream.runForEach((n) => Console.log(n))
)
})
Effect.runPromise(program)
// Output:
// 2
// 4
// 6
Stream<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>): Stream<A, never, R>A, function (type parameter) E in <A, E, R>(self: Stream<A, E, R>): Stream<A, never, R>E, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>): Stream<A, never, 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, E, R>(self: Stream<A, E, R>): Stream<A, never, R>A, never, function (type parameter) R in <A, E, R>(self: Stream<A, E, R>): Stream<A, never, R>R> = dual<(...args: Array<any>) => any, <A, E, R>(self: Stream<A, E, R>, options?: {
readonly log?: boolean | Severity | undefined;
} | undefined) => Stream<A, never, R>>(isDataFirst: (args: IArguments) => boolean, body: <A, E, R>(self: Stream<A, E, R>, options?: {
readonly log?: boolean | Severity | undefined;
} | undefined) => Stream<A, never, R>): ((...args: Array<any>) => any) & (<A, E, R>(self: Stream<A, E, R>, options?: {
readonly log?: boolean | Severity | undefined;
} | undefined) => Stream<A, never, R>) (+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(
(args: IArgumentsargs) => 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: IArgumentsargs[0]),
<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>, options?: {
readonly log?: boolean | Severity | undefined;
} | undefined): Stream<A, never, R>
function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, options?: {
readonly log?: boolean | Severity | undefined;
} | undefined): Stream<A, never, R>
function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, options?: {
readonly log?: boolean | Severity | undefined;
} | undefined): Stream<A, never, R>
self: Stream<A, E, R>(parameter) self: {
channel: Channel.Channel<Arr.NonEmptyReadonlyArray<A>, E, void, unknown, unknown, unknown, R>;
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
}
interface Stream<out A, out E = never, out R = never>A Stream<A, E, R> describes a program that can emit many A values, fail
with E, and require R.
Details
Streams are pull-based with backpressure and emit chunks to amortize effect
evaluation. They support monadic composition and error handling similar to
Effect, adapted for multiple values.
Example (Creating and consuming streams)
import { Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
yield* Stream.make(1, 2, 3).pipe(
Stream.map((n) => n * 2),
Stream.runForEach((n) => Console.log(n))
)
})
Effect.runPromise(program)
// Output:
// 2
// 4
// 6
Stream<function (type parameter) A in <A, E, R>(self: Stream<A, E, R>, options?: {
readonly log?: boolean | Severity | undefined;
} | undefined): Stream<A, never, R>
function (type parameter) E in <A, E, R>(self: Stream<A, E, R>, options?: {
readonly log?: boolean | Severity | undefined;
} | undefined): Stream<A, never, R>
function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, options?: {
readonly log?: boolean | Severity | undefined;
} | undefined): Stream<A, never, R>
options: | {
readonly log?:
| boolean
| Severity
| undefined
}
| undefined
log?: boolean | Severity | undefinedlog?: boolean | type Severity = "Fatal" | "Error" | "Warn" | "Info" | "Debug" | "Trace"Log levels that represent actual message severities, excluding the All and
None sentinel levels.
When to use
Use when typing emitted log message severities, such as explicit log calls,
current log level references, or error-report severity annotations, where
All and None are not valid values.
Severity | 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) A in <A, E, R>(self: Stream<A, E, R>, options?: {
readonly log?: boolean | Severity | undefined;
} | undefined): Stream<A, never, R>
function (type parameter) R in <A, E, R>(self: Stream<A, E, R>, options?: {
readonly log?: boolean | Severity | undefined;
} | undefined): Stream<A, never, R>
const fromChannel: <
Arr extends Arr.NonEmptyReadonlyArray<any>,
E,
R
>(
channel: Channel.Channel<
Arr,
E,
void,
unknown,
unknown,
unknown,
R
>
) => Stream<
Arr extends Arr.NonEmptyReadonlyArray<infer A>
? A
: never,
E,
R
>
Creates a stream from a array-emitting Channel.
Example (Creating a stream from an array-emitting channel)
import { Channel, Console, Effect, Stream } from "effect"
const program = Effect.gen(function*() {
const channel = Channel.succeed([1, 2, 3] as const)
const stream = Stream.fromChannel(channel)
const result = yield* Stream.runCollect(stream)
yield* Console.log(result)
})
// Output: [ 1, 2, 3 ]
fromChannel(import ChannelChannel.const ignoreCause: <
Arg extends
| Channel<any, any, any, any, any, any, any>
| {
readonly log?:
| boolean
| Severity
| undefined
}
| undefined = {
readonly log?: boolean | Severity | undefined
}
>(
selfOrOptions: Arg,
options?:
| {
readonly log?:
| boolean
| Severity
| undefined
}
| undefined
) => [Arg] extends [
Channel<
infer OutElem,
infer _OutErr,
infer OutDone,
infer InElem,
infer InErr,
infer InDone,
infer Env
>
]
? Channel<
OutElem,
never,
OutDone | void,
InElem,
InErr,
InDone,
Env
>
: <
OutElem,
OutErr,
OutDone,
InElem,
InErr,
InDone,
Env
>(
self: Channel<
OutElem,
OutErr,
OutDone,
InElem,
InErr,
InDone,
Env
>
) => Channel<
OutElem,
never,
OutDone | void,
InElem,
InErr,
InDone,
Env
>
Ignores all errors in the channel including defects, converting them to an empty channel.
When to use
Use when a channel should become best-effort and all failure causes, including
defects and interruptions, can be converted to empty output.
Details
Use the log option to emit the full
Cause
when the channel fails.
ignoreCause(self: Stream<A, E, R>(parameter) self: {
channel: Channel.Channel<Arr.NonEmptyReadonlyArray<A>, E, void, unknown, unknown, unknown, R>;
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
}
Stream<A, E, R>.channel: Channel.Channel<Arr.NonEmptyReadonlyArray<A>, E, void, unknown, unknown, unknown, R>(property) Stream<A, E, R>.channel: {
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
}
options: | {
readonly log?:
| boolean
| Severity
| undefined
}
| undefined