<A, B, E2, R2>(f: (a: NoInfer<A>) => Effect<B, E2, R2>): <E, R>(
self: Effect<A, E, R>
) => Effect<A, E | E2, R | R2>
<B, E2, R2>(f: Effect<B, E2, R2>): <A, E, R>(
self: Effect<A, E, R>
) => Effect<A, E | E2, R | R2>
<A, E, R, B, E2, R2>(
self: Effect<A, E, R>,
f: (a: NoInfer<A>) => Effect<B, E2, R2>
): Effect<A, E | E2, R | R2>
<A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: Effect<B, E2, R2>): Effect<
A,
E | E2,
R | R2
>Runs a side effect with the result of an effect without changing the original value.
When to use
Use when you need to run an effectful observation, such as logging or tracking, while passing the original success value to the next step.
Details
tap works similarly to flatMap, but it ignores the result of the function
passed to it. The value from the previous effect remains available for the
next part of the chain. Note that if the side effect fails, the entire chain
will fail too.
Example (Logging a step in a pipeline)
import { Console, Data, Effect, pipe } from "effect"
class DiscountRateError extends Data.TaggedError("DiscountRateError")<{}> {}
// Function to apply a discount safely to a transaction amount
const applyDiscount = (
total: number,
discountRate: number
): Effect.Effect<number, DiscountRateError> =>
discountRate === 0
? Effect.fail(new DiscountRateError())
: Effect.succeed(total - (total * discountRate) / 100)
// Simulated asynchronous task to fetch a transaction amount from database
const fetchTransactionAmount = Effect.promise(() => Promise.resolve(100))
const finalAmount = pipe(
fetchTransactionAmount,
// Log the fetched transaction amount
Effect.tap((amount) => Console.log(`Apply a discount to: ${amount}`)),
// `amount` is still available!
Effect.flatMap((amount) => applyDiscount(amount, 5))
)
Effect.runPromise(finalAmount).then(console.log)
// Output:
// Apply a discount to: 100
// 95export const const tap: {
<A, B, E2, R2>(
f: (a: NoInfer<A>) => Effect<B, E2, R2>
): <E, R>(
self: Effect<A, E, R>
) => Effect<A, E | E2, R | R2>
<B, E2, R2>(f: Effect<B, E2, R2>): <A, E, R>(
self: Effect<A, E, R>
) => Effect<A, E | E2, R | R2>
<A, E, R, B, E2, R2>(
self: Effect<A, E, R>,
f: (a: NoInfer<A>) => Effect<B, E2, R2>
): Effect<A, E | E2, R | R2>
<A, E, R, B, E2, R2>(
self: Effect<A, E, R>,
f: Effect<B, E2, R2>
): Effect<A, E | E2, R | R2>
}
Runs a side effect with the result of an effect without changing the original
value.
When to use
Use when you need to run an effectful observation, such as logging or
tracking, while passing the original success value to the next step.
Details
tap works similarly to flatMap, but it ignores the result of the function
passed to it. The value from the previous effect remains available for the
next part of the chain. Note that if the side effect fails, the entire chain
will fail too.
Example (Logging a step in a pipeline)
import { Console, Data, Effect, pipe } from "effect"
class DiscountRateError extends Data.TaggedError("DiscountRateError")<{}> {}
// Function to apply a discount safely to a transaction amount
const applyDiscount = (
total: number,
discountRate: number
): Effect.Effect<number, DiscountRateError> =>
discountRate === 0
? Effect.fail(new DiscountRateError())
: Effect.succeed(total - (total * discountRate) / 100)
// Simulated asynchronous task to fetch a transaction amount from database
const fetchTransactionAmount = Effect.promise(() => Promise.resolve(100))
const finalAmount = pipe(
fetchTransactionAmount,
// Log the fetched transaction amount
Effect.tap((amount) => Console.log(`Apply a discount to: ${amount}`)),
// `amount` is still available!
Effect.flatMap((amount) => applyDiscount(amount, 5))
)
Effect.runPromise(finalAmount).then(console.log)
// Output:
// Apply a discount to: 100
// 95
tap: {
<function (type parameter) A in <A, B, E2, R2>(f: (a: NoInfer<A>) => Effect<B, E2, R2>): <E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, R | R2>A, function (type parameter) B in <A, B, E2, R2>(f: (a: NoInfer<A>) => Effect<B, E2, R2>): <E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, R | R2>B, function (type parameter) E2 in <A, B, E2, R2>(f: (a: NoInfer<A>) => Effect<B, E2, R2>): <E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, R | R2>E2, function (type parameter) R2 in <A, B, E2, R2>(f: (a: NoInfer<A>) => Effect<B, E2, R2>): <E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, R | R2>R2>(
f: (a: NoInfer<A>) => Effect<B, E2, R2>f: (a: NoInfer<A>a: type NoInfer<A> = [A][A extends any ? 0 : never]Prevents TypeScript from inferring a type parameter from a specific
position.
When to use
Use when a function parameter must match an inferred type without becoming
an inference source.
Details
The parameter using NoInfer must still match the inferred type.
Example (Controlling inference)
import type { Types } from "effect"
declare function withDefault<T>(value: T, fallback: Types.NoInfer<T>): T
// T is inferred as "a" | "b" from the first argument only
const result = withDefault<"a" | "b">("a", "b")
NoInfer<function (type parameter) A in <A, B, E2, R2>(f: (a: NoInfer<A>) => Effect<B, E2, R2>): <E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, R | R2>A>) => interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<function (type parameter) B in <A, B, E2, R2>(f: (a: NoInfer<A>) => Effect<B, E2, R2>): <E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, R | R2>B, function (type parameter) E2 in <A, B, E2, R2>(f: (a: NoInfer<A>) => Effect<B, E2, R2>): <E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, R | R2>E2, function (type parameter) R2 in <A, B, E2, R2>(f: (a: NoInfer<A>) => Effect<B, E2, R2>): <E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, R | R2>R2>
): <function (type parameter) E in <E, R>(self: Effect<A, E, R>): Effect<A, E | E2, R | R2>E, function (type parameter) R in <E, R>(self: Effect<A, E, R>): Effect<A, E | E2, R | R2>R>(self: Effect<A, E, R>(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; <…;
toString: () => string;
toJSON: () => unknown;
}
interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<function (type parameter) A in <A, B, E2, R2>(f: (a: NoInfer<A>) => Effect<B, E2, R2>): <E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, R | R2>A, function (type parameter) E in <E, R>(self: Effect<A, E, R>): Effect<A, E | E2, R | R2>E, function (type parameter) R in <E, R>(self: Effect<A, E, R>): Effect<A, E | E2, R | R2>R>) => interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<function (type parameter) A in <A, B, E2, R2>(f: (a: NoInfer<A>) => Effect<B, E2, R2>): <E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, R | R2>A, function (type parameter) E in <E, R>(self: Effect<A, E, R>): Effect<A, E | E2, R | R2>E | function (type parameter) E2 in <A, B, E2, R2>(f: (a: NoInfer<A>) => Effect<B, E2, R2>): <E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, R | R2>E2, function (type parameter) R in <E, R>(self: Effect<A, E, R>): Effect<A, E | E2, R | R2>R | function (type parameter) R2 in <A, B, E2, R2>(f: (a: NoInfer<A>) => Effect<B, E2, R2>): <E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, R | R2>R2>
<function (type parameter) B in <B, E2, R2>(f: Effect<B, E2, R2>): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, R | R2>B, function (type parameter) E2 in <B, E2, R2>(f: Effect<B, E2, R2>): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, R | R2>E2, function (type parameter) R2 in <B, E2, R2>(f: Effect<B, E2, R2>): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, R | R2>R2>(
f: Effect<B, E2, R2>(parameter) f: {
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;
}
interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<function (type parameter) B in <B, E2, R2>(f: Effect<B, E2, R2>): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, R | R2>B, function (type parameter) E2 in <B, E2, R2>(f: Effect<B, E2, R2>): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, R | R2>E2, function (type parameter) R2 in <B, E2, R2>(f: Effect<B, E2, R2>): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, R | R2>R2>
): <function (type parameter) A in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | E2, R | R2>A, function (type parameter) E in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | E2, R | R2>E, function (type parameter) R in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | E2, R | R2>R>(self: Effect<A, E, R>(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; <…;
toString: () => string;
toJSON: () => unknown;
}
interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<function (type parameter) A in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | E2, R | R2>A, function (type parameter) E in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | E2, R | R2>E, function (type parameter) R in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | E2, R | R2>R>) => interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<function (type parameter) A in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | E2, R | R2>A, function (type parameter) E in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | E2, R | R2>E | function (type parameter) E2 in <B, E2, R2>(f: Effect<B, E2, R2>): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, R | R2>E2, function (type parameter) R in <A, E, R>(self: Effect<A, E, R>): Effect<A, E | E2, R | R2>R | function (type parameter) R2 in <B, E2, R2>(f: Effect<B, E2, R2>): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E | E2, R | R2>R2>
<function (type parameter) A in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: (a: NoInfer<A>) => Effect<B, E2, R2>): Effect<A, E | E2, R | R2>A, function (type parameter) E in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: (a: NoInfer<A>) => Effect<B, E2, R2>): Effect<A, E | E2, R | R2>E, function (type parameter) R in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: (a: NoInfer<A>) => Effect<B, E2, R2>): Effect<A, E | E2, R | R2>R, function (type parameter) B in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: (a: NoInfer<A>) => Effect<B, E2, R2>): Effect<A, E | E2, R | R2>B, function (type parameter) E2 in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: (a: NoInfer<A>) => Effect<B, E2, R2>): Effect<A, E | E2, R | R2>E2, function (type parameter) R2 in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: (a: NoInfer<A>) => Effect<B, E2, R2>): Effect<A, E | E2, R | R2>R2>(
self: Effect<A, E, R>(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; <…;
toString: () => string;
toJSON: () => unknown;
}
interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<function (type parameter) A in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: (a: NoInfer<A>) => Effect<B, E2, R2>): Effect<A, E | E2, R | R2>A, function (type parameter) E in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: (a: NoInfer<A>) => Effect<B, E2, R2>): Effect<A, E | E2, R | R2>E, function (type parameter) R in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: (a: NoInfer<A>) => Effect<B, E2, R2>): Effect<A, E | E2, R | R2>R>,
f: (a: NoInfer<A>) => Effect<B, E2, R2>f: (a: NoInfer<A>a: type NoInfer<A> = [A][A extends any ? 0 : never]Prevents TypeScript from inferring a type parameter from a specific
position.
When to use
Use when a function parameter must match an inferred type without becoming
an inference source.
Details
The parameter using NoInfer must still match the inferred type.
Example (Controlling inference)
import type { Types } from "effect"
declare function withDefault<T>(value: T, fallback: Types.NoInfer<T>): T
// T is inferred as "a" | "b" from the first argument only
const result = withDefault<"a" | "b">("a", "b")
NoInfer<function (type parameter) A in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: (a: NoInfer<A>) => Effect<B, E2, R2>): Effect<A, E | E2, R | R2>A>) => interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<function (type parameter) B in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: (a: NoInfer<A>) => Effect<B, E2, R2>): Effect<A, E | E2, R | R2>B, function (type parameter) E2 in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: (a: NoInfer<A>) => Effect<B, E2, R2>): Effect<A, E | E2, R | R2>E2, function (type parameter) R2 in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: (a: NoInfer<A>) => Effect<B, E2, R2>): Effect<A, E | E2, R | R2>R2>
): interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<function (type parameter) A in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: (a: NoInfer<A>) => Effect<B, E2, R2>): Effect<A, E | E2, R | R2>A, function (type parameter) E in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: (a: NoInfer<A>) => Effect<B, E2, R2>): Effect<A, E | E2, R | R2>E | function (type parameter) E2 in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: (a: NoInfer<A>) => Effect<B, E2, R2>): Effect<A, E | E2, R | R2>E2, function (type parameter) R in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: (a: NoInfer<A>) => Effect<B, E2, R2>): Effect<A, E | E2, R | R2>R | function (type parameter) R2 in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: (a: NoInfer<A>) => Effect<B, E2, R2>): Effect<A, E | E2, R | R2>R2>
<function (type parameter) A in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: Effect<B, E2, R2>): Effect<A, E | E2, R | R2>A, function (type parameter) E in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: Effect<B, E2, R2>): Effect<A, E | E2, R | R2>E, function (type parameter) R in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: Effect<B, E2, R2>): Effect<A, E | E2, R | R2>R, function (type parameter) B in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: Effect<B, E2, R2>): Effect<A, E | E2, R | R2>B, function (type parameter) E2 in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: Effect<B, E2, R2>): Effect<A, E | E2, R | R2>E2, function (type parameter) R2 in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: Effect<B, E2, R2>): Effect<A, E | E2, R | R2>R2>(
self: Effect<A, E, R>(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; <…;
toString: () => string;
toJSON: () => unknown;
}
interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<function (type parameter) A in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: Effect<B, E2, R2>): Effect<A, E | E2, R | R2>A, function (type parameter) E in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: Effect<B, E2, R2>): Effect<A, E | E2, R | R2>E, function (type parameter) R in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: Effect<B, E2, R2>): Effect<A, E | E2, R | R2>R>,
f: Effect<B, E2, R2>(parameter) f: {
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;
}
interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<function (type parameter) B in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: Effect<B, E2, R2>): Effect<A, E | E2, R | R2>B, function (type parameter) E2 in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: Effect<B, E2, R2>): Effect<A, E | E2, R | R2>E2, function (type parameter) R2 in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: Effect<B, E2, R2>): Effect<A, E | E2, R | R2>R2>
): interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<function (type parameter) A in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: Effect<B, E2, R2>): Effect<A, E | E2, R | R2>A, function (type parameter) E in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: Effect<B, E2, R2>): Effect<A, E | E2, R | R2>E | function (type parameter) E2 in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: Effect<B, E2, R2>): Effect<A, E | E2, R | R2>E2, function (type parameter) R in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: Effect<B, E2, R2>): Effect<A, E | E2, R | R2>R | function (type parameter) R2 in <A, E, R, B, E2, R2>(self: Effect<A, E, R>, f: Effect<B, E2, R2>): Effect<A, E | E2, R | R2>R2>
} = import internalinternal.const tap: {
<A, B, E2, R2>(
f: (a: NoInfer<A>) => Effect.Effect<B, E2, R2>
): <E, R>(
self: Effect.Effect<A, E, R>
) => Effect.Effect<A, E | E2, R | R2>
<B, E2, R2>(f: Effect.Effect<B, E2, R2>): <
A,
E,
R
>(
self: Effect.Effect<A, E, R>
) => Effect.Effect<A, E | E2, R | R2>
<A, E, R, B, E2, R2>(
self: Effect.Effect<A, E, R>,
f: (a: NoInfer<A>) => Effect.Effect<B, E2, R2>
): Effect.Effect<A, E | E2, R | R2>
<A, E, R, B, E2, R2>(
self: Effect.Effect<A, E, R>,
f: Effect.Effect<B, E2, R2>
): Effect.Effect<A, E | E2, R | R2>
}