<A extends Request.Any>(
runAll: (
entries: NonEmptyArray<Request.Entry<A>>,
key: unknown
) => Effect.Effect<void, Request.Error<A>>
): RequestResolver<A>Constructs a request resolver with the specified method to run requests.
Example (Creating a request resolver)
import { Effect, Exit, Request, RequestResolver } from "effect"
// Define a request type
interface GetUserRequest extends Request.Request<string, Error> {
readonly _tag: "GetUserRequest"
readonly id: number
}
const GetUserRequest = Request.tagged<GetUserRequest>("GetUserRequest")
// Create a resolver that handles the requests
const UserResolver = RequestResolver.make<GetUserRequest>((entries) =>
Effect.sync(() => {
for (const entry of entries) {
// Complete each request with a result
entry.completeUnsafe(Exit.succeed(`User ${entry.request.id}`))
}
})
)
// Use the resolver to handle requests
const getUserEffect = Effect.request(GetUserRequest({ id: 123 }), UserResolver)export const const make: <A extends Request.Any>(
runAll: (
entries: NonEmptyArray<Request.Entry<A>>,
key: unknown
) => Effect.Effect<void, Request.Error<A>>
) => RequestResolver<A>
Constructs a request resolver with the specified method to run requests.
Example (Creating a request resolver)
import { Effect, Exit, Request, RequestResolver } from "effect"
// Define a request type
interface GetUserRequest extends Request.Request<string, Error> {
readonly _tag: "GetUserRequest"
readonly id: number
}
const GetUserRequest = Request.tagged<GetUserRequest>("GetUserRequest")
// Create a resolver that handles the requests
const UserResolver = RequestResolver.make<GetUserRequest>((entries) =>
Effect.sync(() => {
for (const entry of entries) {
// Complete each request with a result
entry.completeUnsafe(Exit.succeed(`User ${entry.request.id}`))
}
})
)
// Use the resolver to handle requests
const getUserEffect = Effect.request(GetUserRequest({ id: 123 }), UserResolver)
make = <function (type parameter) A in <A extends Request.Any>(runAll: (entries: NonEmptyArray<Request.Entry<A>>, key: unknown) => Effect.Effect<void, Request.Error<A>>): RequestResolver<A>A extends import RequestRequest.type Any = Request.Request<any, any, any>Alias for any Request, regardless of its success, error, or service
requirements.
When to use
Use as a generic constraint for APIs that accept any request while preserving
each concrete request's success, error, and service types.
Any>(
runAll: (
entries: NonEmptyArray<Request.Entry<A>>,
key: unknown
) => Effect.Effect<void, Request.Error<A>>
entries: NonEmptyArray<Request.Entry<A>>(parameter) entries: {
0: Request.Entry<A>;
length: number;
toString: () => string;
toLocaleString: { (): string; (locales: string | string[], options?: Intl.NumberFormatOptions & Intl.DateTimeFormatOptions): string };
pop: () => Request.Entry<A> | undefined;
push: (...items: Array<Request.Entry<A>>) => number;
concat: { (...items: Array<ConcatArray<Request.Entry<A>>>): Array<Request.Entry<A>>; (...items: Array<Request.Entry<A> | ConcatArray<Request.Entry<A>>>): Array<Request.Entry<A>> };
join: (separator?: string) => string;
reverse: () => Array<Request.Entry<A>>;
shift: () => Request.Entry<A> | undefined;
slice: (start?: number, end?: number) => Array<Request.Entry<A>>;
sort: (compareFn?: ((a: Request.Entry<A>, b: Request.Entry<A>) => number) | undefined) => [Request.Entry<A>, ...Request.Entry<A>[]];
splice: { (start: number, deleteCount?: number): Array<Request.Entry<A>>; (start: number, deleteCount: number, ...items: Array<Request.Entry<A>>): Array<Request.Entry<A>> };
unshift: (...items: Array<Request.Entry<A>>) => number;
indexOf: (searchElement: Request.Entry<A>, fromIndex?: number) => number;
lastIndexOf: (searchElement: Request.Entry<A>, fromIndex?: number) => number;
every: { (predicate: (value: Request.Entry<A>, index: number, array: Array<Request.Entry<A>>) => value is S, thisArg?: any): this is S[]; (predicate: (value: Request.Entry<A>, index: number, array: Array<Request.Entry<A>>) => unknown, thisArg?: a…;
some: (predicate: (value: Request.Entry<A>, index: number, array: Array<Request.Entry<A>>) => unknown, thisArg?: any) => boolean;
forEach: (callbackfn: (value: Request.Entry<A>, index: number, array: Array<Request.Entry<A>>) => void, thisArg?: any) => void;
map: (callbackfn: (value: Request.Entry<A>, index: number, array: Array<Request.Entry<A>>) => U, thisArg?: any) => Array<U>;
filter: { (predicate: (value: Request.Entry<A>, index: number, array: Array<Request.Entry<A>>) => value is S, thisArg?: any): Array<S>; (predicate: (value: Request.Entry<A>, index: number, array: Array<Request.Entry<A>>) => unknown, thisArg?: any)…;
reduce: { (callbackfn: (previousValue: Request.Entry<A>, currentValue: Request.Entry<A>, currentIndex: number, array: Array<Request.Entry<A>>) => Request.Entry<A>): Request.Entry<A>; (callbackfn: (previousValue: Request.Entry<A>, currentValue: Req…;
reduceRight: { (callbackfn: (previousValue: Request.Entry<A>, currentValue: Request.Entry<A>, currentIndex: number, array: Array<Request.Entry<A>>) => Request.Entry<A>): Request.Entry<A>; (callbackfn: (previousValue: Request.Entry<A>, currentValue: Req…;
find: { (predicate: (value: Request.Entry<A>, index: number, obj: Array<Request.Entry<A>>) => value is S, thisArg?: any): S | undefined; (predicate: (value: Request.Entry<A>, index: number, obj: Array<Request.Entry<A>>) => unknown, thisArg?: any…;
findIndex: (predicate: (value: Request.Entry<A>, index: number, obj: Array<Request.Entry<A>>) => unknown, thisArg?: any) => number;
fill: (value: Request.Entry<A>, start?: number, end?: number) => [Request.Entry<A>, ...Request.Entry<A>[]];
copyWithin: (target: number, start: number, end?: number) => [Request.Entry<A>, ...Request.Entry<A>[]];
entries: () => ArrayIterator<[number, Request.Entry<A>]>;
keys: () => ArrayIterator<number>;
values: () => ArrayIterator<Request.Entry<A>>;
includes: (searchElement: Request.Entry<A>, fromIndex?: number) => boolean;
flatMap: (callback: (this: This, value: Request.Entry<A>, index: number, array: Array<Request.Entry<A>>) => U | ReadonlyArray<U>, thisArg?: This | undefined) => Array<U>;
flat: (this: A, depth?: D | undefined) => Array<FlatArray<A, D>>;
at: (index: number) => Request.Entry<A> | undefined;
findLast: { (predicate: (value: Request.Entry<A>, index: number, array: Array<Request.Entry<A>>) => value is S, thisArg?: any): S | undefined; (predicate: (value: Request.Entry<A>, index: number, array: Array<Request.Entry<A>>) => unknown, thisArg?:…;
findLastIndex: (predicate: (value: Request.Entry<A>, index: number, array: Array<Request.Entry<A>>) => unknown, thisArg?: any) => number;
toReversed: () => Array<Request.Entry<A>>;
toSorted: (compareFn?: ((a: Request.Entry<A>, b: Request.Entry<A>) => number) | undefined) => Array<Request.Entry<A>>;
toSpliced: { (start: number, deleteCount: number, ...items: Array<Request.Entry<A>>): Array<Request.Entry<A>>; (start: number, deleteCount?: number): Array<Request.Entry<A>> };
with: (index: number, value: Request.Entry<A>) => Array<Request.Entry<A>>;
}
type NonEmptyArray<A> = [A, ...A[]]A mutable array guaranteed to have at least one element.
When to use
Use when mutation is acceptable and non-emptiness must be tracked at the type
level.
Details
This is the mutable counterpart of
NonEmptyReadonlyArray
. Most Array
module functions return NonEmptyArray when the result is guaranteed
non-empty.
Example (Typing a mutable non-empty array)
import type { Array } from "effect"
const nonEmpty: Array.NonEmptyArray<number> = [1, 2, 3]
nonEmpty.push(4)
NonEmptyArray<import RequestRequest.interface Entry<out R>A pending request handed to a RequestResolver.
Details
An entry contains the original request, the fiber context needed to run it,
an uninterruptible flag used by batching and caching internals, and the
completeUnsafe callback used by resolvers to supply the final Exit.
Entry<function (type parameter) A in <A extends Request.Any>(runAll: (entries: NonEmptyArray<Request.Entry<A>>, key: unknown) => Effect.Effect<void, Request.Error<A>>): RequestResolver<A>A>>, key: unknownkey: unknown) => import EffectEffect.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<void, import RequestRequest.type Error<
T extends Request.Request<any, any, any>
> = [T] extends [
Request.Request<infer _A, infer _E, infer _R>
]
? _E
: never
A utility type to extract the error type from a Request.
Example (Extracting a request error type)
import type { Request } from "effect"
interface GetUser extends Request.Request<string, Error> {
readonly id: number
}
// Extract the error type from a Request using the utility
type UserError = Request.Error<GetUser> // Error
Error<function (type parameter) A in <A extends Request.Any>(runAll: (entries: NonEmptyArray<Request.Entry<A>>, key: unknown) => Effect.Effect<void, Request.Error<A>>): RequestResolver<A>A>>
): interface RequestResolver<in A extends Request.Any>A resolver that executes and completes batched Request entries.
Details
A resolver controls how requests are grouped, delayed, optionally
pre-checked, and finally run. Its runAll method receives a non-empty batch
of Request.Entry values for a single batch key and must complete every
received entry, usually by calling completeUnsafe or one of the Request
completion helpers.
Gotchas
If a resolver finishes without completing an entry, the waiting request fails
because the resolver did not supply a result.
Example (Defining a request resolver)
import { Effect, Exit, RequestResolver } from "effect"
import type { Request } from "effect"
interface GetUserRequest extends Request.Request<string, Error> {
readonly _tag: "GetUserRequest"
readonly id: number
}
// In practice, you would typically use RequestResolver.make() instead
const resolver = RequestResolver.make<GetUserRequest>((entries) =>
Effect.sync(() => {
for (const entry of entries) {
entry.completeUnsafe(Exit.succeed(`User ${entry.request.id}`))
}
})
)
Namespace containing type-level helpers associated with RequestResolver.
RequestResolver<function (type parameter) A in <A extends Request.Any>(runAll: (entries: NonEmptyArray<Request.Entry<A>>, key: unknown) => Effect.Effect<void, Request.Error<A>>): RequestResolver<A>A> =>
const makeWith: <
A extends Request.Any
>(options: {
readonly batchKey: (
request: Request.Entry<A>
) => unknown
readonly preCheck?:
| ((entry: Request.Entry<A>) => boolean)
| undefined
readonly delay: Effect.Effect<void>
readonly collectWhile: (
requests: ReadonlySet<Request.Entry<A>>
) => boolean
readonly runAll: (
entries: NonEmptyArray<Request.Entry<A>>,
key: unknown
) => Effect.Effect<void, Request.Error<A>>
}) => RequestResolver<A>
Creates a request resolver with fine-grained
control over its behavior.
When to use
Use when you need to supply the resolver batching primitives directly,
including the batch key, optional pre-check, delay effect, collection cutoff,
and batch runner.
Details
batchKey groups request entries, delay schedules batch execution,
collectWhile can end collection early, and runAll receives a non-empty
batch for one key.
Gotchas
Accepted entries must be completed. If runAll succeeds with incomplete
entries, waiting requests fail. If preCheck returns false, the entry is
not batched, so it must be completed or linked to another completion path.
makeWith({
batchKey: (request: Request.Entry<A>) => unknownbatchKey: const defaultKey: (
_request: unknown
) => unknown
delay: Effect.Effect<void, never, never>(property) delay: {
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 yieldNow: Effect<void>const yieldNow: {
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;
}
Yields control back to the Effect runtime, allowing other fibers to execute.
Example (Yielding to other fibers)
import { Effect } from "effect"
const program = Effect.gen(function*() {
console.log("Before yield")
yield* Effect.yieldNow
console.log("After yield")
})
Effect.runPromise(program)
yieldNow,
collectWhile: LazyArg<boolean>collectWhile: const constTrue: LazyArg<boolean>Returns true when called.
When to use
Use when you need a thunk that returns true on every invocation.
Example (Returning true from a thunk)
import { Function } from "effect"
import * as assert from "node:assert"
assert.deepStrictEqual(Function.constTrue(), true)
constTrue,
runAll: (
entries: NonEmptyArray<Request.Entry<A>>,
key: unknown
) => Effect.Effect<void, Request.Error<A>>