<XR>(context: Context.Context<XR>): <A, E, R>(
self: Effect<A, E, R>
) => Effect<A, E, Exclude<R, XR>>
<A, E, R, XR>(
self: Effect<A, E, R>,
context: Context.Context<XR>
): Effect<A, E, Exclude<R, XR>>Provides a context to an effect, fulfilling its service requirements.
Details
This function provides multiple services at once by supplying a context that contains all the required services. It removes the provided services from the effect's requirements, making them available to the effect.
Example (Providing a complete context)
import { Context, Effect } from "effect"
// Define service keys
const Logger = Context.Service<{
log: (msg: string) => void
}>("Logger")
const Database = Context.Service<{
query: (sql: string) => string
}>("Database")
// Create a context with multiple services
const context = Context.make(Logger, { log: console.log })
.pipe(Context.add(Database, { query: () => "result" }))
// An effect that requires both services
const program = Effect.gen(function*() {
const logger = yield* Effect.service(Logger)
const db = yield* Effect.service(Database)
logger.log("Querying database")
return db.query("SELECT * FROM users")
})
const provided = Effect.provideContext(program, context)export const const provideContext: {
<XR>(context: Context.Context<XR>): <A, E, R>(
self: Effect<A, E, R>
) => Effect<A, E, Exclude<R, XR>>
<A, E, R, XR>(
self: Effect<A, E, R>,
context: Context.Context<XR>
): Effect<A, E, Exclude<R, XR>>
}
Provides a context to an effect, fulfilling its service requirements.
Details
This function provides multiple services at once by supplying a context
that contains all the required services. It removes the provided services
from the effect's requirements, making them available to the effect.
Example (Providing a complete context)
import { Context, Effect } from "effect"
// Define service keys
const Logger = Context.Service<{
log: (msg: string) => void
}>("Logger")
const Database = Context.Service<{
query: (sql: string) => string
}>("Database")
// Create a context with multiple services
const context = Context.make(Logger, { log: console.log })
.pipe(Context.add(Database, { query: () => "result" }))
// An effect that requires both services
const program = Effect.gen(function*() {
const logger = yield* Effect.service(Logger)
const db = yield* Effect.service(Database)
logger.log("Querying database")
return db.query("SELECT * FROM users")
})
const provided = Effect.provideContext(program, context)
provideContext: {
<function (type parameter) XR in <XR>(context: Context.Context<XR>): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E, Exclude<R, XR>>XR>(
context: Context.Context<XR>(parameter) context: {
mapUnsafe: ReadonlyMap<string, any>;
mutable: boolean;
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 ContextContext.type Context.Context = /*unresolved*/ anyContext<function (type parameter) XR in <XR>(context: Context.Context<XR>): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E, Exclude<R, XR>>XR>
): <function (type parameter) A in <A, E, R>(self: Effect<A, E, R>): Effect<A, E, Exclude<R, XR>>A, function (type parameter) E in <A, E, R>(self: Effect<A, E, R>): Effect<A, E, Exclude<R, XR>>E, function (type parameter) R in <A, E, R>(self: Effect<A, E, R>): Effect<A, E, Exclude<R, XR>>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, Exclude<R, XR>>A, function (type parameter) E in <A, E, R>(self: Effect<A, E, R>): Effect<A, E, Exclude<R, XR>>E, function (type parameter) R in <A, E, R>(self: Effect<A, E, R>): Effect<A, E, Exclude<R, XR>>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, Exclude<R, XR>>A, function (type parameter) E in <A, E, R>(self: Effect<A, E, R>): Effect<A, E, Exclude<R, XR>>E, type Exclude<T, U> = T extends U
? never
: T
Exclude from T those types that are assignable to U
Exclude<function (type parameter) R in <A, E, R>(self: Effect<A, E, R>): Effect<A, E, Exclude<R, XR>>R, function (type parameter) XR in <XR>(context: Context.Context<XR>): <A, E, R>(self: Effect<A, E, R>) => Effect<A, E, Exclude<R, XR>>XR>>
<function (type parameter) A in <A, E, R, XR>(self: Effect<A, E, R>, context: Context.Context<XR>): Effect<A, E, Exclude<R, XR>>A, function (type parameter) E in <A, E, R, XR>(self: Effect<A, E, R>, context: Context.Context<XR>): Effect<A, E, Exclude<R, XR>>E, function (type parameter) R in <A, E, R, XR>(self: Effect<A, E, R>, context: Context.Context<XR>): Effect<A, E, Exclude<R, XR>>R, function (type parameter) XR in <A, E, R, XR>(self: Effect<A, E, R>, context: Context.Context<XR>): Effect<A, E, Exclude<R, XR>>XR>(
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, XR>(self: Effect<A, E, R>, context: Context.Context<XR>): Effect<A, E, Exclude<R, XR>>A, function (type parameter) E in <A, E, R, XR>(self: Effect<A, E, R>, context: Context.Context<XR>): Effect<A, E, Exclude<R, XR>>E, function (type parameter) R in <A, E, R, XR>(self: Effect<A, E, R>, context: Context.Context<XR>): Effect<A, E, Exclude<R, XR>>R>,
context: Context.Context<XR>(parameter) context: {
mapUnsafe: ReadonlyMap<string, any>;
mutable: boolean;
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 ContextContext.type Context.Context = /*unresolved*/ anyContext<function (type parameter) XR in <A, E, R, XR>(self: Effect<A, E, R>, context: Context.Context<XR>): Effect<A, E, Exclude<R, XR>>XR>
): 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, XR>(self: Effect<A, E, R>, context: Context.Context<XR>): Effect<A, E, Exclude<R, XR>>A, function (type parameter) E in <A, E, R, XR>(self: Effect<A, E, R>, context: Context.Context<XR>): Effect<A, E, Exclude<R, XR>>E, type Exclude<T, U> = T extends U
? never
: T
Exclude from T those types that are assignable to U
Exclude<function (type parameter) R in <A, E, R, XR>(self: Effect<A, E, R>, context: Context.Context<XR>): Effect<A, E, Exclude<R, XR>>R, function (type parameter) XR in <A, E, R, XR>(self: Effect<A, E, R>, context: Context.Context<XR>): Effect<A, E, Exclude<R, XR>>XR>>
} = import internalinternal.const provideContext: {
<XR>(context: Context.Context<XR>): <A, E, R>(
self: Effect.Effect<A, E, R>
) => Effect.Effect<A, E, Exclude<R, XR>>
<A, E, R, XR>(
self: Effect.Effect<A, E, R>,
context: Context.Context<XR>
): Effect.Effect<A, E, Exclude<R, XR>>
}