<A, E = never>(): Effect.Effect<TxDeferred<A, E>>Creates a new empty TxDeferred.
When to use
Use to create a transactional deferred that can be completed exactly once.
Example (Creating a transactional deferred)
import { Effect, Option, TxDeferred } from "effect"
const program = Effect.gen(function*() {
const deferred = yield* TxDeferred.make<string, Error>()
const state = yield* TxDeferred.poll(deferred)
console.log(Option.isNone(state)) // true
})export const const make: <
A,
E = never
>() => Effect.Effect<TxDeferred<A, E>>
Creates a new empty TxDeferred.
When to use
Use to create a transactional deferred that can be completed exactly once.
Example (Creating a transactional deferred)
import { Effect, Option, TxDeferred } from "effect"
const program = Effect.gen(function*() {
const deferred = yield* TxDeferred.make<string, Error>()
const state = yield* TxDeferred.poll(deferred)
console.log(Option.isNone(state)) // true
})
make = <function (type parameter) A in <A, E = never>(): Effect.Effect<TxDeferred<A, E>>A, function (type parameter) E in <A, E = never>(): Effect.Effect<TxDeferred<A, E>>E = never>(): import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<interface TxDeferred<in out A, in out E = never>A transactional deferred is a write-once cell readable within transactions.
Readers block (retry the transaction) until a value is committed, and writers
succeed only on the first call; subsequent writes return false.
When to use
Use to coordinate transaction-local readers and one-time completion with a
success or failure result.
Example (Completing a transactional deferred)
import { Effect, TxDeferred } from "effect"
const program = Effect.gen(function*() {
const deferred = yield* TxDeferred.make<number>()
// Complete the deferred
const first = yield* TxDeferred.succeed(deferred, 42)
console.log(first) // true
// Second write is a no-op
const second = yield* TxDeferred.succeed(deferred, 99)
console.log(second) // false
// Read the value
const value = yield* TxDeferred.await(deferred)
console.log(value) // 42
})
TxDeferred<function (type parameter) A in <A, E = never>(): Effect.Effect<TxDeferred<A, E>>A, function (type parameter) E in <A, E = never>(): Effect.Effect<TxDeferred<A, E>>E>> =>
import EffectEffect.map(import TxRefTxRef.const make: <Option<Result<A, E>>>(initial: Option<Result<A, E>>) => anyCreates a new TxRef with the specified initial value.
When to use
Use to create a TxRef inside an Effect workflow.
Example (Creating transactional references)
import { Effect, TxRef } from "effect"
const program = Effect.gen(function*() {
// Create a transactional reference with initial value
const counter = yield* TxRef.make(0)
const name = yield* TxRef.make("Alice")
// Use in transactions
yield* Effect.tx(Effect.gen(function*() {
yield* TxRef.set(counter, 42)
yield* TxRef.set(name, "Bob")
}))
console.log(yield* TxRef.get(counter)) // 42
console.log(yield* TxRef.get(name)) // "Bob"
})
make<import OptionOption<import ResultResult<function (type parameter) A in <A, E = never>(): Effect.Effect<TxDeferred<A, E>>A, function (type parameter) E in <A, E = never>(): Effect.Effect<TxDeferred<A, E>>E>>>(import OO.none()), const makeTxDeferred: <A, E>(
ref: TxRef.TxRef<Option<Result<A, E>>>
) => TxDeferred<A, E>