<OutElem, B, X, EX, RX>(
filter: Filter.FilterEffect<OutElem, B, X, EX, RX>
): <OutErr, OutDone, InElem, InErr, InDone, Env>(
self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>
) => Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>
<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(
self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>,
filter: Filter.FilterEffect<OutElem, B, X, EX, RX>
): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>Filters and maps output elements using an effectful Filter.
When to use
Use to apply effectful logic that can discard channel output elements and emit transformed values for the elements that pass.
Details
Successful filter results are emitted as mapped values. Failed filter results are discarded. Failures from the effectful filter fail the returned channel.
Source effect/Channel.ts:331629 lines
export const const filterMapEffect: {
<OutElem, B, X, EX, RX>(
filter: Filter.FilterEffect<
OutElem,
B,
X,
EX,
RX
>
): <
OutErr,
OutDone,
InElem,
InErr,
InDone,
Env
>(
self: Channel<
OutElem,
OutErr,
OutDone,
InElem,
InErr,
InDone,
Env
>
) => Channel<
B,
OutErr | EX,
OutDone,
InElem,
InErr,
InDone,
Env | RX
>
<
OutElem,
OutErr,
OutDone,
InElem,
InErr,
InDone,
Env,
B,
X,
EX,
RX
>(
self: Channel<
OutElem,
OutErr,
OutDone,
InElem,
InErr,
InDone,
Env
>,
filter: Filter.FilterEffect<
OutElem,
B,
X,
EX,
RX
>
): Channel<
B,
OutErr | EX,
OutDone,
InElem,
InErr,
InDone,
Env | RX
>
}
Filters and maps output elements using an effectful Filter.
When to use
Use to apply effectful logic that can discard channel output elements and
emit transformed values for the elements that pass.
Details
Successful filter results are emitted as mapped values. Failed filter
results are discarded. Failures from the effectful filter fail the returned
channel.
filterMapEffect: {
<function (type parameter) OutElem in <OutElem, B, X, EX, RX>(filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>) => Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutElem, function (type parameter) B in <OutElem, B, X, EX, RX>(filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>) => Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>B, function (type parameter) X in <OutElem, B, X, EX, RX>(filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>) => Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>X, function (type parameter) EX in <OutElem, B, X, EX, RX>(filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>) => Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>EX, function (type parameter) RX in <OutElem, B, X, EX, RX>(filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>) => Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>RX>(
filter: Filter.FilterEffect<
OutElem,
B,
X,
EX,
RX
>
import FilterFilter.interface FilterEffect<in Input, out Pass, out Fail, out E = never, out R = never>Represents an effectful filter function that can produce Effects.
Details
Similar to a regular Filter, but the filtering operation itself can be
effectful, allowing for asynchronous operations, error handling, and
dependency injection.
Example (Defining an effectful user filter)
import { Effect, Filter, Result } from "effect"
// An effectful filter that validates user data
type User = { id: string; isActive: boolean }
type ValidationError = { message: string }
const validateUser: Filter.FilterEffect<
string,
User,
User,
ValidationError,
never
> = (id) =>
Effect.gen(function*() {
const user: User = { id, isActive: id.length > 0 }
return user.isActive ? Result.succeed(user) : Result.fail(user)
})
FilterEffect<function (type parameter) OutElem in <OutElem, B, X, EX, RX>(filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>) => Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutElem, function (type parameter) B in <OutElem, B, X, EX, RX>(filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>) => Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>B, function (type parameter) X in <OutElem, B, X, EX, RX>(filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>) => Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>X, function (type parameter) EX in <OutElem, B, X, EX, RX>(filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>) => Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>EX, function (type parameter) RX in <OutElem, B, X, EX, RX>(filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>) => Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>RX>
): <function (type parameter) OutErr in <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutErr, function (type parameter) OutDone in <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutDone, function (type parameter) InElem in <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InElem, function (type parameter) InErr in <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InErr, function (type parameter) InDone in <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InDone, function (type parameter) Env in <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>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, B, X, EX, RX>(filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>) => Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutElem, function (type parameter) OutErr in <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutErr, function (type parameter) OutDone in <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutDone, function (type parameter) InElem in <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InElem, function (type parameter) InErr in <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InErr, function (type parameter) InDone in <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InDone, function (type parameter) Env in <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>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) B in <OutElem, B, X, EX, RX>(filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>) => Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>B, function (type parameter) OutErr in <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutErr | function (type parameter) EX in <OutElem, B, X, EX, RX>(filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>) => Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>EX, function (type parameter) OutDone in <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutDone, function (type parameter) InElem in <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InElem, function (type parameter) InErr in <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InErr, function (type parameter) InDone in <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InDone, function (type parameter) Env in <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>Env | function (type parameter) RX in <OutElem, B, X, EX, RX>(filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): <OutErr, OutDone, InElem, InErr, InDone, Env>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>) => Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>RX>
<function (type parameter) OutElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutElem, function (type parameter) OutErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutErr, function (type parameter) OutDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutDone, function (type parameter) InElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InElem, function (type parameter) InErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InErr, function (type parameter) InDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InDone, function (type parameter) Env in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>Env, function (type parameter) B in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>B, function (type parameter) X in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>X, function (type parameter) EX in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>EX, function (type parameter) RX in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>RX>(
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, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutElem, function (type parameter) OutErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutErr, function (type parameter) OutDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutDone, function (type parameter) InElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InElem, function (type parameter) InErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InErr, function (type parameter) InDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InDone, function (type parameter) Env in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>Env>,
filter: Filter.FilterEffect<
OutElem,
B,
X,
EX,
RX
>
import FilterFilter.interface FilterEffect<in Input, out Pass, out Fail, out E = never, out R = never>Represents an effectful filter function that can produce Effects.
Details
Similar to a regular Filter, but the filtering operation itself can be
effectful, allowing for asynchronous operations, error handling, and
dependency injection.
Example (Defining an effectful user filter)
import { Effect, Filter, Result } from "effect"
// An effectful filter that validates user data
type User = { id: string; isActive: boolean }
type ValidationError = { message: string }
const validateUser: Filter.FilterEffect<
string,
User,
User,
ValidationError,
never
> = (id) =>
Effect.gen(function*() {
const user: User = { id, isActive: id.length > 0 }
return user.isActive ? Result.succeed(user) : Result.fail(user)
})
FilterEffect<function (type parameter) OutElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutElem, function (type parameter) B in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>B, function (type parameter) X in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>X, function (type parameter) EX in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>EX, function (type parameter) RX in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>RX>
): 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) B in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>B, function (type parameter) OutErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutErr | function (type parameter) EX in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>EX, function (type parameter) OutDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutDone, function (type parameter) InElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InElem, function (type parameter) InErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InErr, function (type parameter) InDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InDone, function (type parameter) Env in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>Env | function (type parameter) RX in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>RX>
} = dual<(...args: Array<any>) => any, <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>) => Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>>(arity: 2, body: <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>) => Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>): ((...args: Array<any>) => any) & (<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>) => Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>) (+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, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutElem, function (type parameter) OutErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutErr, function (type parameter) OutDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutDone, function (type parameter) InElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InElem, function (type parameter) InErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InErr, function (type parameter) InDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InDone, function (type parameter) Env in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>Env, function (type parameter) B in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>B, function (type parameter) X in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>X, function (type parameter) EX in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>EX, function (type parameter) RX in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>RX>(
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, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutElem, function (type parameter) OutErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutErr, function (type parameter) OutDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutDone, function (type parameter) InElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InElem, function (type parameter) InErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InErr, function (type parameter) InDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InDone, function (type parameter) Env in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>Env>,
filter: Filter.FilterEffect<
OutElem,
B,
X,
EX,
RX
>
import FilterFilter.interface FilterEffect<in Input, out Pass, out Fail, out E = never, out R = never>Represents an effectful filter function that can produce Effects.
Details
Similar to a regular Filter, but the filtering operation itself can be
effectful, allowing for asynchronous operations, error handling, and
dependency injection.
Example (Defining an effectful user filter)
import { Effect, Filter, Result } from "effect"
// An effectful filter that validates user data
type User = { id: string; isActive: boolean }
type ValidationError = { message: string }
const validateUser: Filter.FilterEffect<
string,
User,
User,
ValidationError,
never
> = (id) =>
Effect.gen(function*() {
const user: User = { id, isActive: id.length > 0 }
return user.isActive ? Result.succeed(user) : Result.fail(user)
})
FilterEffect<function (type parameter) OutElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutElem, function (type parameter) B in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>B, function (type parameter) X in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>X, function (type parameter) EX in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>EX, function (type parameter) RX in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>RX>
): 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) B in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>B, function (type parameter) OutErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutErr | function (type parameter) EX in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>EX, function (type parameter) OutDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutDone, function (type parameter) InElem in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InElem, function (type parameter) InErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InErr, function (type parameter) InDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>InDone, function (type parameter) Env in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>Env | function (type parameter) RX in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>RX> =>
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((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;
}
import EffectEffect.const map: {
<A, B>(f: (a: A) => B): <E, R>(
self: Effect<A, E, R>
) => Effect<B, E, R>
<A, E, R, B>(
self: Effect<A, E, R>,
f: (a: A) => B
): Effect<B, E, R>
}
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;
}
pull: Pull.Pull<
OutElem,
OutErr,
OutDone,
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;
}
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>
}
pull: Pull.Pull<
OutElem,
OutErr,
OutDone,
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;
}
function (local function) loop(elem: OutElem): Pull.Pull<B, OutErr | EX, OutDone, RX>loop(elem: OutElemelem): 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<function (type parameter) B in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>B, function (type parameter) OutErr in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutErr | function (type parameter) EX in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>EX, function (type parameter) OutDone in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>OutDone, function (type parameter) RX in <OutElem, OutErr, OutDone, InElem, InErr, InDone, Env, B, X, EX, RX>(self: Channel<OutElem, OutErr, OutDone, InElem, InErr, InDone, Env>, filter: Filter.FilterEffect<OutElem, B, X, EX, RX>): Channel<B, OutErr | EX, OutDone, InElem, InErr, InDone, Env | RX>RX> {
return 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>
}
filter: Filter.FilterEffect<
OutElem,
B,
X,
EX,
RX
>
elem: OutElemelem),
(result: Result.Result<B, X>result) =>
import ResultResult.const isFailure: <A, E>(
self: Result<A, E>
) => self is Failure<A, E>
Checks whether a Result is a Failure.
When to use
Use to narrow a known Result to the Failure variant.
Details
- Acts as a TypeScript type guard, narrowing to
Failure<A, E>
- After narrowing, you can access
.failure to read the error value
Example (Narrowing to failure)
import { Result } from "effect"
const result = Result.fail("oops")
if (Result.isFailure(result)) {
console.log(result.failure)
// Output: "oops"
}
isFailure(result: Result.Result<B, X>result)
? 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>
}
pull: Pull.Pull<
OutElem,
OutErr,
OutDone,
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;
}
function (local function) loop(elem: OutElem): Pull.Pull<B, OutErr | EX, OutDone, RX>loop)
: import EffectEffect.const succeed: <A>(value: A) => Effect<A>Creates an Effect that always succeeds with a given value.
When to use
Use when an effect should complete successfully with a specific value without any errors
or external dependencies.
Example (Creating a successful effect)
import { Effect } from "effect"
// Creating an effect that represents a successful scenario
//
// ┌─── Effect<number, never, never>
// ▼
const success = Effect.succeed(42)
succeed(result: Result.Success<B, X>(parameter) result: {
_tag: "Success";
_op: "Success";
success: A;
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;
}
Success<B, X>.success: Bsuccess)
)
})
)
))