<A, E>(self: Enqueue<A, E>, message: Types.NoInfer<A>): Effect<boolean>Adds a message to the queue. Returns false if the queue is done.
Details
For bounded queues, this operation may suspend if the queue is at capacity, depending on the backpressure strategy. For dropping/sliding queues, it may return false or succeed immediately by dropping/sliding existing messages.
Example (Offering a value)
import { Effect, Queue } from "effect"
const program = Effect.gen(function*() {
const queue = yield* Queue.bounded<number>(3)
// Successfully add messages to queue
const success1 = yield* Queue.offer(queue, 1)
const success2 = yield* Queue.offer(queue, 2)
console.log(success1, success2) // true, true
// Queue state
const size = yield* Queue.size(queue)
console.log(size) // 2
})Offering
Source effect/Queue.ts:63225 lines
export const const offer: <A, E>(
self: Enqueue<A, E>,
message: Types.NoInfer<A>
) => Effect<boolean>
Adds a message to the queue. Returns false if the queue is done.
Details
For bounded queues, this operation may suspend if the queue is at capacity,
depending on the backpressure strategy. For dropping/sliding queues, it may
return false or succeed immediately by dropping/sliding existing messages.
Example (Offering a value)
import { Effect, Queue } from "effect"
const program = Effect.gen(function*() {
const queue = yield* Queue.bounded<number>(3)
// Successfully add messages to queue
const success1 = yield* Queue.offer(queue, 1)
const success2 = yield* Queue.offer(queue, 2)
console.log(success1, success2) // true, true
// Queue state
const size = yield* Queue.size(queue)
console.log(size) // 2
})
offer = <function (type parameter) A in <A, E>(self: Enqueue<A, E>, message: Types.NoInfer<A>): Effect<boolean>A, function (type parameter) E in <A, E>(self: Enqueue<A, E>, message: Types.NoInfer<A>): Effect<boolean>E>(self: Enqueue<A, E>(parameter) self: {
strategy: "suspend" | "dropping" | "sliding";
dispatcher: SchedulerDispatcher;
capacity: number;
messages: MutableList.MutableList<any>;
state: Queue.State<any, any>;
scheduleRunning: boolean;
toString: () => string;
toJSON: () => unknown;
}
interface Enqueue<in A, in E = never>An Enqueue is a queue that can be offered to.
Details
This interface represents the write-only part of a Queue, allowing you to offer
elements to the queue but not take elements from it.
Example (Offering through enqueue handles)
import { Effect, Queue } from "effect"
// Function that only needs write access to a queue
const producer = (enqueue: Queue.Enqueue<string>) =>
Effect.gen(function*() {
yield* Queue.offer(enqueue, "hello")
yield* Queue.offerAll(enqueue, ["world", "!"])
})
const program = Effect.gen(function*() {
const queue = yield* Queue.bounded<string>(10)
yield* producer(queue)
})
Companion namespace containing type-level metadata for the Enqueue
write-only queue interface.
Enqueue<function (type parameter) A in <A, E>(self: Enqueue<A, E>, message: Types.NoInfer<A>): Effect<boolean>A, function (type parameter) E in <A, E>(self: Enqueue<A, E>, message: Types.NoInfer<A>): Effect<boolean>E>, message: Types.NoInfer<A>message: import TypesTypes.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>(self: Enqueue<A, E>, message: Types.NoInfer<A>): Effect<boolean>A>): import EffectEffect<boolean> =>
import internalEffectinternalEffect.const suspend: <A, E, R>(
evaluate: LazyArg<Effect.Effect<A, E, R>>
) => Effect.Effect<A, E, R>
self: Enqueue<A, E>(parameter) self: {
strategy: "suspend" | "dropping" | "sliding";
dispatcher: SchedulerDispatcher;
capacity: number;
messages: MutableList.MutableList<any>;
state: Queue.State<any, any>;
scheduleRunning: boolean;
toString: () => string;
toJSON: () => unknown;
}
Enqueue<in A, in E = never>.state: Queue.State<any, any>state._tag: "Open" | "Closing" | "Done"_tag !== "Open") {
return const exitFalse: Exit<boolean, never>exitFalse
} else if (self: Enqueue<A, E>(parameter) self: {
strategy: "suspend" | "dropping" | "sliding";
dispatcher: SchedulerDispatcher;
capacity: number;
messages: MutableList.MutableList<any>;
state: Queue.State<any, any>;
scheduleRunning: boolean;
toString: () => string;
toJSON: () => unknown;
}
Enqueue<in A, in E = never>.messages: MutableList.MutableList<any>(property) Enqueue<in A, in E = never>.messages: {
head: MutableList.Bucket<A> | undefined;
tail: MutableList.Bucket<A> | undefined;
length: number;
}
self: Enqueue<A, E>(parameter) self: {
strategy: "suspend" | "dropping" | "sliding";
dispatcher: SchedulerDispatcher;
capacity: number;
messages: MutableList.MutableList<any>;
state: Queue.State<any, any>;
scheduleRunning: boolean;
toString: () => string;
toJSON: () => unknown;
}
Enqueue<in A, in E = never>.capacity: numbercapacity) {
switch (self: Enqueue<A, E>(parameter) self: {
strategy: "suspend" | "dropping" | "sliding";
dispatcher: SchedulerDispatcher;
capacity: number;
messages: MutableList.MutableList<any>;
state: Queue.State<any, any>;
scheduleRunning: boolean;
toString: () => string;
toJSON: () => unknown;
}
Enqueue<in A, in E = never>.strategy: "suspend" | "dropping" | "sliding"strategy) {
case "dropping":
return const exitFalse: Exit<boolean, never>exitFalse
case "suspend":
if (self: Enqueue<A, E>(parameter) self: {
strategy: "suspend" | "dropping" | "sliding";
dispatcher: SchedulerDispatcher;
capacity: number;
messages: MutableList.MutableList<any>;
state: Queue.State<any, any>;
scheduleRunning: boolean;
toString: () => string;
toJSON: () => unknown;
}
Enqueue<in A, in E = never>.capacity: numbercapacity <= 0 && self: Enqueue<A, E>(parameter) self: {
strategy: "suspend" | "dropping" | "sliding";
dispatcher: SchedulerDispatcher;
capacity: number;
messages: MutableList.MutableList<any>;
state: Queue.State<any, any>;
scheduleRunning: boolean;
toString: () => string;
toJSON: () => unknown;
}
Enqueue<in A, in E = never>.state: {
readonly _tag: "Open";
readonly takers: Set<(_: Effect<void, any>) => void>;
readonly offers: Set<Queue.OfferEntry<any>>;
readonly awaiters: Set<(_: Effect<void, any>) => void>;
}
takers: Set<(_: Effect<void, E>) => void>takers.Set<(_: Effect<void, any>) => void>.size: numbersize > 0) {
import MutableListMutableList.append(self: Enqueue<A, E>(parameter) self: {
strategy: "suspend" | "dropping" | "sliding";
dispatcher: SchedulerDispatcher;
capacity: number;
messages: MutableList.MutableList<any>;
state: Queue.State<any, any>;
scheduleRunning: boolean;
toString: () => string;
toJSON: () => unknown;
}
Enqueue<in A, in E = never>.messages: MutableList.MutableList<any>(property) Enqueue<in A, in E = never>.messages: {
head: MutableList.Bucket<A> | undefined;
tail: MutableList.Bucket<A> | undefined;
length: number;
}
message: Types.NoInfer<A>message)
const releaseTakers: <A, E>(
self: Enqueue<A, E>
) => void
self: Enqueue<A, E>(parameter) self: {
strategy: "suspend" | "dropping" | "sliding";
dispatcher: SchedulerDispatcher;
capacity: number;
messages: MutableList.MutableList<any>;
state: Queue.State<any, any>;
scheduleRunning: boolean;
toString: () => string;
toJSON: () => unknown;
}
interface Queue<in out A, in out E = never>A Queue is an asynchronous queue that can be offered to and taken from.
Details
It also supports signaling that it is done or failed.
Example (Offering and taking queue values)
import { Effect, Queue } from "effect"
const program = Effect.gen(function*() {
// Create a bounded queue
const queue = yield* Queue.bounded<string>(10)
// Producer: offer items to the queue
yield* Queue.offer(queue, "hello")
yield* Queue.offerAll(queue, ["world", "!"])
// Consumer: take items from the queue
const item1 = yield* Queue.take(queue)
const item2 = yield* Queue.take(queue)
const item3 = yield* Queue.take(queue)
console.log([item1, item2, item3]) // ["hello", "world", "!"]
})
Companion namespace containing type-level metadata and low-level state types
for Queue.
Queue<function (type parameter) A in <A, E>(self: Enqueue<A, E>, message: Types.NoInfer<A>): Effect<boolean>A, function (type parameter) E in <A, E>(self: Enqueue<A, E>, message: Types.NoInfer<A>): Effect<boolean>E>)
return const exitTrue: Exit<boolean, never>exitTrue
}
return const offerRemainingSingle: <A, E>(
self: Enqueue<A, E>,
message: A
) => Effect<boolean, never, never>
self: Enqueue<A, E>(parameter) self: {
strategy: "suspend" | "dropping" | "sliding";
dispatcher: SchedulerDispatcher;
capacity: number;
messages: MutableList.MutableList<any>;
state: Queue.State<any, any>;
scheduleRunning: boolean;
toString: () => string;
toJSON: () => unknown;
}
interface Queue<in out A, in out E = never>A Queue is an asynchronous queue that can be offered to and taken from.
Details
It also supports signaling that it is done or failed.
Example (Offering and taking queue values)
import { Effect, Queue } from "effect"
const program = Effect.gen(function*() {
// Create a bounded queue
const queue = yield* Queue.bounded<string>(10)
// Producer: offer items to the queue
yield* Queue.offer(queue, "hello")
yield* Queue.offerAll(queue, ["world", "!"])
// Consumer: take items from the queue
const item1 = yield* Queue.take(queue)
const item2 = yield* Queue.take(queue)
const item3 = yield* Queue.take(queue)
console.log([item1, item2, item3]) // ["hello", "world", "!"]
})
Companion namespace containing type-level metadata and low-level state types
for Queue.
Queue<function (type parameter) A in <A, E>(self: Enqueue<A, E>, message: Types.NoInfer<A>): Effect<boolean>A, function (type parameter) E in <A, E>(self: Enqueue<A, E>, message: Types.NoInfer<A>): Effect<boolean>E>, message: Types.NoInfer<A>message)
case "sliding":
import MutableListMutableList.take(self: Enqueue<A, E>(parameter) self: {
strategy: "suspend" | "dropping" | "sliding";
dispatcher: SchedulerDispatcher;
capacity: number;
messages: MutableList.MutableList<any>;
state: Queue.State<any, any>;
scheduleRunning: boolean;
toString: () => string;
toJSON: () => unknown;
}
Enqueue<in A, in E = never>.messages: MutableList.MutableList<any>(property) Enqueue<in A, in E = never>.messages: {
head: MutableList.Bucket<A> | undefined;
tail: MutableList.Bucket<A> | undefined;
length: number;
}
import MutableListMutableList.append(self: Enqueue<A, E>(parameter) self: {
strategy: "suspend" | "dropping" | "sliding";
dispatcher: SchedulerDispatcher;
capacity: number;
messages: MutableList.MutableList<any>;
state: Queue.State<any, any>;
scheduleRunning: boolean;
toString: () => string;
toJSON: () => unknown;
}
Enqueue<in A, in E = never>.messages: MutableList.MutableList<any>(property) Enqueue<in A, in E = never>.messages: {
head: MutableList.Bucket<A> | undefined;
tail: MutableList.Bucket<A> | undefined;
length: number;
}
message: Types.NoInfer<A>message)
return const exitTrue: Exit<boolean, never>exitTrue
}
}
import MutableListMutableList.append(self: Enqueue<A, E>(parameter) self: {
strategy: "suspend" | "dropping" | "sliding";
dispatcher: SchedulerDispatcher;
capacity: number;
messages: MutableList.MutableList<any>;
state: Queue.State<any, any>;
scheduleRunning: boolean;
toString: () => string;
toJSON: () => unknown;
}
Enqueue<in A, in E = never>.messages: MutableList.MutableList<any>(property) Enqueue<in A, in E = never>.messages: {
head: MutableList.Bucket<A> | undefined;
tail: MutableList.Bucket<A> | undefined;
length: number;
}
message: Types.NoInfer<A>message)
const scheduleReleaseTaker: <A, E>(
self: Enqueue<A, E>
) => void
self: Enqueue<A, E>(parameter) self: {
strategy: "suspend" | "dropping" | "sliding";
dispatcher: SchedulerDispatcher;
capacity: number;
messages: MutableList.MutableList<any>;
state: Queue.State<any, any>;
scheduleRunning: boolean;
toString: () => string;
toJSON: () => unknown;
}
interface Queue<in out A, in out E = never>A Queue is an asynchronous queue that can be offered to and taken from.
Details
It also supports signaling that it is done or failed.
Example (Offering and taking queue values)
import { Effect, Queue } from "effect"
const program = Effect.gen(function*() {
// Create a bounded queue
const queue = yield* Queue.bounded<string>(10)
// Producer: offer items to the queue
yield* Queue.offer(queue, "hello")
yield* Queue.offerAll(queue, ["world", "!"])
// Consumer: take items from the queue
const item1 = yield* Queue.take(queue)
const item2 = yield* Queue.take(queue)
const item3 = yield* Queue.take(queue)
console.log([item1, item2, item3]) // ["hello", "world", "!"]
})
Companion namespace containing type-level metadata and low-level state types
for Queue.
Queue<function (type parameter) A in <A, E>(self: Enqueue<A, E>, message: Types.NoInfer<A>): Effect<boolean>A, function (type parameter) E in <A, E>(self: Enqueue<A, E>, message: Types.NoInfer<A>): Effect<boolean>E>)
return const exitTrue: Exit<boolean, never>exitTrue
})Referenced by 6 symbols