(
options:
| { readonly capacity: "unbounded" }
| {
readonly capacity: number
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined
}
): <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(
self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
) => Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(
self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>,
options:
| { readonly capacity: "unbounded" }
| {
readonly capacity: number
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined
}
): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>Buffers individual output elements in a queue with the configured capacity
so a faster producer can progress independently of a slower consumer.
When to use
Use when output elements can be decoupled from downstream demand and the configured backpressure or loss strategy is acceptable.
Details
Finite queues use the strategy option. The default "suspend" strategy
applies backpressure, while "dropping" and "sliding" can discard output
elements when the queue is full. "unbounded" capacity does not use a finite
capacity strategy.
Gotchas
Dropping and sliding strategies can lose output elements under backpressure.
BufferingbufferArray
Source effect/Channel.ts:674738 lines
export const const buffer: {
(
options:
| { readonly capacity: "unbounded" }
| {
readonly capacity: number
readonly strategy?:
| "dropping"
| "sliding"
| "suspend"
| undefined
}
): <
OutElem,
OutErr,
OutDone,
InElem,
InErr,
InDone,
Env
>(
self: Channel<
OutElem,
OutErr,
OutDone,
InElem,
InErr,
InDone,
Env
>
) => Channel<
OutElem,
OutErr,
OutDone,
InElem,
InErr,
InDone,
Env
>
<
OutElem,
OutErr,
OutDone,
InElem,
InErr,
InDone,
Env
>(
self: Channel<
OutElem,
OutErr,
OutDone,
InElem,
InErr,
InDone,
Env
>,
options:
| { readonly capacity: "unbounded" }
| {
readonly capacity: number
readonly strategy?:
| "dropping"
| "sliding"
| "suspend"
| undefined
}
): Channel<
OutElem,
OutErr,
OutDone,
InElem,
InErr,
InDone,
Env
>
}
Buffers individual output elements in a queue with the configured capacity
so a faster producer can progress independently of a slower consumer.
When to use
Use when output elements can be decoupled from downstream demand and the
configured backpressure or loss strategy is acceptable.
Details
Finite queues use the strategy option. The default "suspend" strategy
applies backpressure, while "dropping" and "sliding" can discard output
elements when the queue is full. "unbounded" capacity does not use a finite
capacity strategy.
Gotchas
Dropping and sliding strategies can lose output elements under backpressure.
buffer: {
(
options: | {
readonly capacity: "unbounded"
}
| {
readonly capacity: number
readonly strategy?:
| "dropping"
| "sliding"
| "suspend"
| undefined
}
capacity: "unbounded"capacity: "unbounded" } | {
readonly capacity: numbercapacity: number
readonly strategy?: | "sliding"
| "dropping"
| "suspend"
| undefined
function (type parameter) OutElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>OutElem, function (type parameter) OutErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>OutErr, function (type parameter) OutDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>OutDone, function (type parameter) InElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>InElem, function (type parameter) InErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>InErr, function (type parameter) InDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>InDone, function (type parameter) Env in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>Env>(
self: Channel<
OutElem,
OutErr,
OutDone,
InElem,
InErr,
InDone,
Env
>
(parameter) self: {
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 Channel<out OutElem, out OutErr = never, out OutDone = void, in InElem = unknown, in InErr = unknown, in InDone = unknown, out Env = never>A Channel is a nexus of I/O operations, which supports both reading and
writing. A channel may read values of type InElem and write values of type
OutElem. When the channel finishes, it yields a value of type OutDone. A
channel may fail with a value of type OutErr.
Details
Channels are the foundation of Streams: both streams and sinks are built on
channels. Most users shouldn't have to use channels directly, as streams and
sinks are much more convenient and cover all common use cases. However, when
adding new stream and sink operators, or doing something highly specialized,
it may be useful to use channels directly.
Channels compose in a variety of ways:
- Piping: One channel can be piped to another channel, assuming the
input type of the second is the same as the output type of the first.
- Sequencing: The terminal value of one channel can be used to create
another channel, and both the first channel and the function that makes
the second channel can be composed into a channel.
- Concatenating: The output of one channel can be used to create other
channels, which are all concatenated together. The first channel and the
function that makes the other channels can be composed into a channel.
Example (Typing channels)
import type { Channel } from "effect"
// A channel that outputs numbers and requires no environment
type NumberChannel = Channel.Channel<number>
// A channel that outputs strings, can fail with Error, completes with boolean
type StringChannel = Channel.Channel<string, Error, boolean>
// A channel with all type parameters specified
type FullChannel = Channel.Channel<
string, // OutElem - output elements
Error, // OutErr - output errors
number, // OutDone - completion value
number, // InElem - input elements
string, // InErr - input errors
boolean, // InDone - input completion
{ db: string } // Env - required environment
>
Channel<function (type parameter) OutElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>OutElem, function (type parameter) OutErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>OutErr, function (type parameter) OutDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>OutDone, function (type parameter) InElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>InElem, function (type parameter) InErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>InErr, function (type parameter) InDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>InDone, function (type parameter) Env in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>Env>
) => interface Channel<out OutElem, out OutErr = never, out OutDone = void, in InElem = unknown, in InErr = unknown, in InDone = unknown, out Env = never>A Channel is a nexus of I/O operations, which supports both reading and
writing. A channel may read values of type InElem and write values of type
OutElem. When the channel finishes, it yields a value of type OutDone. A
channel may fail with a value of type OutErr.
Details
Channels are the foundation of Streams: both streams and sinks are built on
channels. Most users shouldn't have to use channels directly, as streams and
sinks are much more convenient and cover all common use cases. However, when
adding new stream and sink operators, or doing something highly specialized,
it may be useful to use channels directly.
Channels compose in a variety of ways:
- Piping: One channel can be piped to another channel, assuming the
input type of the second is the same as the output type of the first.
- Sequencing: The terminal value of one channel can be used to create
another channel, and both the first channel and the function that makes
the second channel can be composed into a channel.
- Concatenating: The output of one channel can be used to create other
channels, which are all concatenated together. The first channel and the
function that makes the other channels can be composed into a channel.
Example (Typing channels)
import type { Channel } from "effect"
// A channel that outputs numbers and requires no environment
type NumberChannel = Channel.Channel<number>
// A channel that outputs strings, can fail with Error, completes with boolean
type StringChannel = Channel.Channel<string, Error, boolean>
// A channel with all type parameters specified
type FullChannel = Channel.Channel<
string, // OutElem - output elements
Error, // OutErr - output errors
number, // OutDone - completion value
number, // InElem - input elements
string, // InErr - input errors
boolean, // InDone - input completion
{ db: string } // Env - required environment
>
Channel<function (type parameter) OutElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>OutElem, function (type parameter) OutErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>OutErr, function (type parameter) OutDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>OutDone, function (type parameter) InElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>InElem, function (type parameter) InErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>InErr, function (type parameter) InDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>InDone, function (type parameter) Env in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>Env>
<function (type parameter) OutElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) OutErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) OutDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) InElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) InErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) InDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) Env in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
self: Channel<
OutElem,
OutErr,
OutDone,
InElem,
InErr,
InDone,
Env
>
(parameter) self: {
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 Channel<out OutElem, out OutErr = never, out OutDone = void, in InElem = unknown, in InErr = unknown, in InDone = unknown, out Env = never>A Channel is a nexus of I/O operations, which supports both reading and
writing. A channel may read values of type InElem and write values of type
OutElem. When the channel finishes, it yields a value of type OutDone. A
channel may fail with a value of type OutErr.
Details
Channels are the foundation of Streams: both streams and sinks are built on
channels. Most users shouldn't have to use channels directly, as streams and
sinks are much more convenient and cover all common use cases. However, when
adding new stream and sink operators, or doing something highly specialized,
it may be useful to use channels directly.
Channels compose in a variety of ways:
- Piping: One channel can be piped to another channel, assuming the
input type of the second is the same as the output type of the first.
- Sequencing: The terminal value of one channel can be used to create
another channel, and both the first channel and the function that makes
the second channel can be composed into a channel.
- Concatenating: The output of one channel can be used to create other
channels, which are all concatenated together. The first channel and the
function that makes the other channels can be composed into a channel.
Example (Typing channels)
import type { Channel } from "effect"
// A channel that outputs numbers and requires no environment
type NumberChannel = Channel.Channel<number>
// A channel that outputs strings, can fail with Error, completes with boolean
type StringChannel = Channel.Channel<string, Error, boolean>
// A channel with all type parameters specified
type FullChannel = Channel.Channel<
string, // OutElem - output elements
Error, // OutErr - output errors
number, // OutDone - completion value
number, // InElem - input elements
string, // InErr - input errors
boolean, // InDone - input completion
{ db: string } // Env - required environment
>
Channel<function (type parameter) OutElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) OutErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) OutDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) InElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) InErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) InDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) Env in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
options: | {
readonly capacity: "unbounded"
}
| {
readonly capacity: number
readonly strategy?:
| "dropping"
| "sliding"
| "suspend"
| undefined
}
capacity: "unbounded"capacity: "unbounded" } | {
readonly capacity: numbercapacity: number
readonly strategy?: | "sliding"
| "dropping"
| "suspend"
| undefined
interface Channel<out OutElem, out OutErr = never, out OutDone = void, in InElem = unknown, in InErr = unknown, in InDone = unknown, out Env = never>A Channel is a nexus of I/O operations, which supports both reading and
writing. A channel may read values of type InElem and write values of type
OutElem. When the channel finishes, it yields a value of type OutDone. A
channel may fail with a value of type OutErr.
Details
Channels are the foundation of Streams: both streams and sinks are built on
channels. Most users shouldn't have to use channels directly, as streams and
sinks are much more convenient and cover all common use cases. However, when
adding new stream and sink operators, or doing something highly specialized,
it may be useful to use channels directly.
Channels compose in a variety of ways:
- Piping: One channel can be piped to another channel, assuming the
input type of the second is the same as the output type of the first.
- Sequencing: The terminal value of one channel can be used to create
another channel, and both the first channel and the function that makes
the second channel can be composed into a channel.
- Concatenating: The output of one channel can be used to create other
channels, which are all concatenated together. The first channel and the
function that makes the other channels can be composed into a channel.
Example (Typing channels)
import type { Channel } from "effect"
// A channel that outputs numbers and requires no environment
type NumberChannel = Channel.Channel<number>
// A channel that outputs strings, can fail with Error, completes with boolean
type StringChannel = Channel.Channel<string, Error, boolean>
// A channel with all type parameters specified
type FullChannel = Channel.Channel<
string, // OutElem - output elements
Error, // OutErr - output errors
number, // OutDone - completion value
number, // InElem - input elements
string, // InErr - input errors
boolean, // InDone - input completion
{ db: string } // Env - required environment
>
Channel<function (type parameter) OutElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) OutErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) OutDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) InElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) InErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) InDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) Env in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
dual<(...args: Array<any>) => any, <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}) => Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>>(arity: 2, body: <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}) => Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): ((...args: Array<any>) => any) & (<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}) => Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>) (+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) OutElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) OutErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) OutDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) InElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) InErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) InDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) Env in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
self: Channel<
OutElem,
OutErr,
OutDone,
InElem,
InErr,
InDone,
Env
>
(parameter) self: {
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 Channel<out OutElem, out OutErr = never, out OutDone = void, in InElem = unknown, in InErr = unknown, in InDone = unknown, out Env = never>A Channel is a nexus of I/O operations, which supports both reading and
writing. A channel may read values of type InElem and write values of type
OutElem. When the channel finishes, it yields a value of type OutDone. A
channel may fail with a value of type OutErr.
Details
Channels are the foundation of Streams: both streams and sinks are built on
channels. Most users shouldn't have to use channels directly, as streams and
sinks are much more convenient and cover all common use cases. However, when
adding new stream and sink operators, or doing something highly specialized,
it may be useful to use channels directly.
Channels compose in a variety of ways:
- Piping: One channel can be piped to another channel, assuming the
input type of the second is the same as the output type of the first.
- Sequencing: The terminal value of one channel can be used to create
another channel, and both the first channel and the function that makes
the second channel can be composed into a channel.
- Concatenating: The output of one channel can be used to create other
channels, which are all concatenated together. The first channel and the
function that makes the other channels can be composed into a channel.
Example (Typing channels)
import type { Channel } from "effect"
// A channel that outputs numbers and requires no environment
type NumberChannel = Channel.Channel<number>
// A channel that outputs strings, can fail with Error, completes with boolean
type StringChannel = Channel.Channel<string, Error, boolean>
// A channel with all type parameters specified
type FullChannel = Channel.Channel<
string, // OutElem - output elements
Error, // OutErr - output errors
number, // OutDone - completion value
number, // InElem - input elements
string, // InErr - input errors
boolean, // InDone - input completion
{ db: string } // Env - required environment
>
Channel<function (type parameter) OutElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) OutErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) OutDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) InElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) InErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) InDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) Env in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
options: | {
readonly capacity: "unbounded"
}
| {
readonly capacity: number
readonly strategy?:
| "dropping"
| "sliding"
| "suspend"
| undefined
}
capacity: "unbounded"capacity: "unbounded" } | {
readonly capacity: numbercapacity: number
readonly strategy?: | "sliding"
| "dropping"
| "suspend"
| undefined
interface Channel<out OutElem, out OutErr = never, out OutDone = void, in InElem = unknown, in InErr = unknown, in InDone = unknown, out Env = never>A Channel is a nexus of I/O operations, which supports both reading and
writing. A channel may read values of type InElem and write values of type
OutElem. When the channel finishes, it yields a value of type OutDone. A
channel may fail with a value of type OutErr.
Details
Channels are the foundation of Streams: both streams and sinks are built on
channels. Most users shouldn't have to use channels directly, as streams and
sinks are much more convenient and cover all common use cases. However, when
adding new stream and sink operators, or doing something highly specialized,
it may be useful to use channels directly.
Channels compose in a variety of ways:
- Piping: One channel can be piped to another channel, assuming the
input type of the second is the same as the output type of the first.
- Sequencing: The terminal value of one channel can be used to create
another channel, and both the first channel and the function that makes
the second channel can be composed into a channel.
- Concatenating: The output of one channel can be used to create other
channels, which are all concatenated together. The first channel and the
function that makes the other channels can be composed into a channel.
Example (Typing channels)
import type { Channel } from "effect"
// A channel that outputs numbers and requires no environment
type NumberChannel = Channel.Channel<number>
// A channel that outputs strings, can fail with Error, completes with boolean
type StringChannel = Channel.Channel<string, Error, boolean>
// A channel with all type parameters specified
type FullChannel = Channel.Channel<
string, // OutElem - output elements
Error, // OutErr - output errors
number, // OutDone - completion value
number, // InElem - input elements
string, // InErr - input errors
boolean, // InDone - input completion
{ db: string } // Env - required environment
>
Channel<function (type parameter) OutElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) OutErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) OutDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) InElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) InErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) InDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) Env in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
const fromTransform: <
OutElem,
OutErr,
OutDone,
InElem,
InErr,
InDone,
EX,
EnvX,
Env
>(
transform: (
upstream: Pull.Pull<InElem, InErr, InDone>,
scope: Scope.Scope
) => Effect.Effect<
Pull.Pull<OutElem, OutErr, OutDone, EnvX>,
EX,
Env
>
) => Channel<
OutElem,
Pull.ExcludeDone<OutErr> | EX,
OutDone,
InElem,
InErr,
InDone,
Env | EnvX
>
Creates a Channel from a transformation function that operates on upstream pulls.
Example (Creating channels from transforms)
import { Channel, Effect } from "effect"
const channel = Channel.fromTransform((upstream, scope) =>
Effect.succeed(upstream)
)
fromTransform(import EffectEffect.const fnUntraced: <Effect.Effect<void, never, never> | Effect.Effect<Pull.Pull<OutElem, OutErr, OutDone, never>, never, Env>, Effect.Effect<OutElem, any, never>, [upstream: Pull.Pull<InElem, InErr, InDone, never>, scope: Scope.Scope]>(body: (this: Types.unassigned, upstream: Pull.Pull<InElem, InErr, InDone, never>, scope: Scope.Scope) => Generator<Effect.Effect<void, never, never> | Effect.Effect<Pull.Pull<...>, never, Env>, Effect.Effect<...>, never>) => (upstream: Pull.Pull<...>, scope: Scope.Scope) => Effect.Effect<...> (+41 overloads)fnUntraced(function*(upstream: Pull.Pull<InElem, InErr, InDone, never>(parameter) upstream: {
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;
}
const pull: Pull.Pull<
OutElem,
OutErr,
OutDone,
never
>
const 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;
}
const toTransform: <
OutElem,
OutErr,
OutDone,
InElem,
InErr,
InDone,
Env
>(
channel: Channel<
OutElem,
OutErr,
OutDone,
InElem,
InErr,
InDone,
Env
>
) => (
upstream: Pull.Pull<InElem, InErr, InDone>,
scope: Scope.Scope
) => Effect.Effect<
Pull.Pull<OutElem, OutErr, OutDone>,
never,
Env
>
Converts a Channel back to its underlying transformation function.
Example (Extracting channel transforms)
import { Channel } from "effect"
const channel = Channel.succeed(42)
const transform = Channel.toTransform(channel)
// transform can now be used directly
toTransform(self: Channel<
OutElem,
OutErr,
OutDone,
InElem,
InErr,
InDone,
Env
>
(parameter) self: {
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; <…;
}
upstream: Pull.Pull<InElem, InErr, InDone, never>(parameter) upstream: {
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;
}
const queue: Queue.Queue<
OutElem,
OutErr | Cause.Done<OutDone>
>
const queue: {
strategy: "suspend" | "dropping" | "sliding";
dispatcher: SchedulerDispatcher;
capacity: number;
messages: MutableList.MutableList<any>;
state: Queue.State<any, any>;
scheduleRunning: boolean;
toString: () => string;
toJSON: () => unknown;
}
import QueueQueue.const make: <A, E = never>(
options?:
| {
readonly capacity?: number | undefined
readonly strategy?:
| "suspend"
| "dropping"
| "sliding"
| undefined
}
| undefined
) => Effect<Queue<A, E>>
Creates a Queue with optional capacity and overflow strategy.
Details
By default the queue is unbounded and uses the "suspend" strategy. Provide
capacity for a bounded queue and choose "suspend", "dropping", or
"sliding" to control what happens when the queue is full. The returned
queue can be offered to, taken from, failed, ended, interrupted, or shut down.
Example (Creating queues)
import { Cause, Effect, Queue } from "effect"
Effect.gen(function*() {
const queue = yield* Queue.make<number, string | Cause.Done>()
// add messages to the queue
yield* Queue.offer(queue, 1)
yield* Queue.offer(queue, 2)
yield* Queue.offerAll(queue, [3, 4, 5])
// take messages from the queue
const messages = yield* Queue.takeAll(queue)
console.log(messages) // [1, 2, 3, 4, 5]
// signal that the queue is done
yield* Queue.end(queue)
const done = yield* Effect.flip(Queue.take(queue))
console.log(Cause.isDone(done)) // true
// signal that another queue has failed
const failedQueue = yield* Queue.make<number, string>()
const failed = yield* Queue.fail(failedQueue, "boom")
console.log(failed) // true
})
make<function (type parameter) OutElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
function (type parameter) OutErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
import CauseCause.type Cause.Done = /*unresolved*/ anyDone<function (type parameter) OutDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, options: {
readonly capacity: "unbounded";
} | {
readonly capacity: number;
readonly strategy?: "dropping" | "sliding" | "suspend" | undefined;
}): Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
capacity?: number | undefinedcapacity: options: | {
readonly capacity: "unbounded"
}
| {
readonly capacity: number
readonly strategy?:
| "dropping"
| "sliding"
| "suspend"
| undefined
}
capacity: number | "unbounded"capacity === "unbounded" ? var undefinedundefined : options: {
readonly capacity: number
readonly strategy?:
| "dropping"
| "sliding"
| "suspend"
| undefined
}
capacity: numbercapacity,
strategy?: | "sliding"
| "dropping"
| "suspend"
| undefined
options: | {
readonly capacity: "unbounded"
}
| {
readonly capacity: number
readonly strategy?:
| "dropping"
| "sliding"
| "suspend"
| undefined
}
capacity: number | "unbounded"capacity === "unbounded" ? var undefinedundefined : options: {
readonly capacity: number
readonly strategy?:
| "dropping"
| "sliding"
| "suspend"
| undefined
}
strategy?: | "sliding"
| "dropping"
| "suspend"
| undefined
import ScopeScope.const addFinalizer: (
scope: Scope,
finalizer: Effect<unknown>
) => Effect<void>
Registers a finalizer effect on a scope.
Details
If the scope is open, the finalizer runs when the scope closes, regardless of
whether the scope closes successfully or with an error. If the scope is
already closed, the finalizer runs immediately.
Example (Adding finalizers)
import { Console, Effect, Exit, Scope } from "effect"
const program = Effect.gen(function*() {
const scope = yield* Scope.make()
// Add simple finalizers
yield* Scope.addFinalizer(scope, Console.log("Cleanup task 1"))
yield* Scope.addFinalizer(scope, Console.log("Cleanup task 2"))
yield* Scope.addFinalizer(scope, Effect.log("Cleanup task 3"))
// Do some work
yield* Console.log("Doing work...")
// Close the scope
yield* Scope.close(scope, Exit.void)
})
addFinalizer(scope: Scope.Scope(parameter) scope: {
strategy: "sequential" | "parallel";
state: State.Open | State.Closed | State.Empty;
}
import QueueQueue.const shutdown: <A, E>(
self: Enqueue<A, E>
) => Effect<boolean>
Shuts down the queue immediately, discarding buffered messages and resuming
pending operations.
Details
The operation is idempotent and returns true, including when the queue has
already been shut down or completed.
Example (Shutting down queues)
import { Effect, Queue } from "effect"
const program = Effect.gen(function*() {
const queue = yield* Queue.bounded<number>(2)
// Add messages
yield* Queue.offer(queue, 1)
yield* Queue.offer(queue, 2)
// Shutdown clears buffered messages and prevents further offers
const wasShutdown = yield* Queue.shutdown(queue)
console.log(wasShutdown) // true
// Queue is now done and cleared
const size = yield* Queue.size(queue)
console.log(size) // 0
})
shutdown(const queue: Queue.Queue<
OutElem,
OutErr | Cause.Done<OutDone>
>
const queue: {
strategy: "suspend" | "dropping" | "sliding";
dispatcher: SchedulerDispatcher;
capacity: number;
messages: MutableList.MutableList<any>;
state: Queue.State<any, any>;
scheduleRunning: boolean;
toString: () => string;
toJSON: () => unknown;
}
const pull: Pull.Pull<
OutElem,
OutErr,
OutDone,
never
>
const 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;
}
Pipeable.pipe<Pull.Pull<OutElem, OutErr, OutDone, never>, Effect.Effect<boolean, any, never>, Effect.Effect<never, any, never>, Effect.Effect<never, any, never>, Effect.Effect<Fiber.Fiber<never, any>, never, never>>(this: Pull.Pull<...>, ab: (_: Pull.Pull<OutElem, OutErr, OutDone, never>) => Effect.Effect<boolean, any, never>, bc: (_: Effect.Effect<boolean, any, never>) => Effect.Effect<never, any, never>, cd: (_: Effect.Effect<never, any, never>) => Effect.Effect<...>, de: (_: Effect.Effect<...>) => Effect.Effect<...>): Effect.Effect<...> (+21 overloads)pipe(
import EffectEffect.const flatMap: {
<A, B, E1, R1>(
f: (a: A) => Effect<B, E1, R1>
): <E, R>(
self: Effect<A, E, R>
) => Effect<B, E1 | E, R1 | R>
<A, E, R, B, E1, R1>(
self: Effect<A, E, R>,
f: (a: A) => Effect<B, E1, R1>
): Effect<B, E | E1, R | R1>
}
value: OutElemvalue) => import QueueQueue.const offer: <A, E>(
self: Enqueue<A, E>,
message: Types.NoInfer<A>
) => Effect<boolean>
Adds a message to the queue. Returns false if the queue is done.
Details
For bounded queues, this operation may suspend if the queue is at capacity,
depending on the backpressure strategy. For dropping/sliding queues, it may
return false or succeed immediately by dropping/sliding existing messages.
Example (Offering a value)
import { Effect, Queue } from "effect"
const program = Effect.gen(function*() {
const queue = yield* Queue.bounded<number>(3)
// Successfully add messages to queue
const success1 = yield* Queue.offer(queue, 1)
const success2 = yield* Queue.offer(queue, 2)
console.log(success1, success2) // true, true
// Queue state
const size = yield* Queue.size(queue)
console.log(size) // 2
})
offer(const queue: Queue.Queue<
OutElem,
OutErr | Cause.Done<OutDone>
>
const queue: {
strategy: "suspend" | "dropping" | "sliding";
dispatcher: SchedulerDispatcher;
capacity: number;
messages: MutableList.MutableList<any>;
state: Queue.State<any, any>;
scheduleRunning: boolean;
toString: () => string;
toJSON: () => unknown;
}
value: OutElemvalue)),
import EffectEffect.const forever: <
Arg extends
| Effect<any, any, any>
| {
readonly disableYield?:
| boolean
| undefined
}
| undefined = {
readonly disableYield?: boolean | undefined
}
>(
effectOrOptions?: Arg,
options?:
| {
readonly disableYield?:
| boolean
| undefined
}
| undefined
) => [Arg] extends [
Effect<infer _A, infer _E, infer _R>
]
? Effect<never, _E, _R>
: <A, E, R>(
self: Effect<A, E, R>
) => Effect<never, E, R>
Repeats this effect forever (until the first error).
Example (Repeating forever)
import { Console, Effect, Fiber } from "effect"
const task = Effect.gen(function*() {
yield* Console.log("Task running...")
yield* Effect.sleep("1 second")
})
// This will run forever, printing every second
const program = task.pipe(Effect.forever)
// This will run forever, without yielding every iteration
const programNoYield = task.pipe(Effect.forever({ disableYield: true }))
// Run for 5 seconds then interrupt
const timedProgram = Effect.gen(function*() {
const fiber = yield* Effect.forkChild(program)
yield* Effect.sleep("5 seconds")
yield* Fiber.interrupt(fiber)
})
forever({ disableYield: truedisableYield: true }),
import EffectEffect.const onError: {
<E, X, R2>(
cleanup: (
cause: Cause.Cause<E>
) => Effect<X, never, R2>
): <A, R>(
self: Effect<A, E, R>
) => Effect<A, E, R2 | R>
<A, E, R, X, R2>(
self: Effect<A, E, R>,
cleanup: (
cause: Cause.Cause<E>
) => Effect<X, never, R2>
): Effect<A, E, R2 | R>
}
cause: Cause.Cause<
OutErr | Cause.Done<OutDone>
>
(parameter) cause: {
reasons: ReadonlyArray<Reason<E>>;
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 QueueQueue.const failCause: {
<E>(cause: Cause<E>): <A>(
self: Enqueue<A, E>
) => Effect<boolean>
<A, E>(
self: Enqueue<A, E>,
cause: Cause<E>
): Effect<boolean>
}
const queue: Queue.Queue<
OutElem,
OutErr | Cause.Done<OutDone>
>
const queue: {
strategy: "suspend" | "dropping" | "sliding";
dispatcher: SchedulerDispatcher;
capacity: number;
messages: MutableList.MutableList<any>;
state: Queue.State<any, any>;
scheduleRunning: boolean;
toString: () => string;
toJSON: () => unknown;
}
cause: Cause.Cause<
OutErr | Cause.Done<OutDone>
>
(parameter) cause: {
reasons: ReadonlyArray<Reason<E>>;
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 EffectEffect.const forkIn: {
(
scope: Scope,
options?: {
readonly startImmediately?:
| boolean
| undefined
readonly uninterruptible?:
| boolean
| "inherit"
| undefined
}
): <A, E, R>(
self: Effect<A, E, R>
) => Effect<Fiber<A, E>, never, R>
<A, E, R>(
self: Effect<A, E, R>,
scope: Scope,
options?: {
readonly startImmediately?:
| boolean
| undefined
readonly uninterruptible?:
| boolean
| "inherit"
| undefined
}
): Effect<Fiber<A, E>, never, R>
}
scope: Scope.Scope(parameter) scope: {
strategy: "sequential" | "parallel";
state: State.Open | State.Closed | State.Empty;
}
import QueueQueue.const take: <A, E>(
self: Dequeue<A, E>
) => Effect<A, E>
Takes a single message from the queue, or wait for a message to be
available.
Details
If the queue is done, it will fail with Done. If the
queue fails, the Effect will fail with the error.
Example (Taking one value)
import { Cause, Effect, Queue } from "effect"
const program = Effect.gen(function*() {
const queue = yield* Queue.bounded<string, Cause.Done>(3)
// Add some messages
yield* Queue.offer(queue, "first")
yield* Queue.offer(queue, "second")
// Take messages one by one
const msg1 = yield* Queue.take(queue)
const msg2 = yield* Queue.take(queue)
console.log(msg1, msg2) // "first", "second"
// End the queue
yield* Queue.end(queue)
// Taking from an ended queue fails with Done
const result = yield* Effect.match(Queue.take(queue), {
onFailure: (error: Cause.Done) => true,
onSuccess: (value: string) => false
})
console.log("Queue ended:", result) // true
})
take(const queue: Queue.Queue<
OutElem,
OutErr | Cause.Done<OutDone>
>
const queue: {
strategy: "suspend" | "dropping" | "sliding";
dispatcher: SchedulerDispatcher;
capacity: number;
messages: MutableList.MutableList<any>;
state: Queue.State<any, any>;
scheduleRunning: boolean;
toString: () => string;
toJSON: () => unknown;
}
Referenced by 1 symbols