(u: unknown): u is TxDeferred<unknown, unknown>Determines if the provided value is a TxDeferred.
When to use
Use to narrow an unknown value before treating it as a transactional deferred.
Example (Checking transactional deferreds)
import { Effect, TxDeferred } from "effect"
const program = Effect.gen(function*() {
const deferred = yield* TxDeferred.make<number>()
console.log(TxDeferred.isTxDeferred(deferred)) // true
console.log(TxDeferred.isTxDeferred("not a deferred")) // false
})guards
Source effect/TxDeferred.ts:3191 lines
export const const isTxDeferred: (
u: unknown
) => u is TxDeferred<unknown, unknown>
Determines if the provided value is a TxDeferred.
When to use
Use to narrow an unknown value before treating it as a transactional deferred.
Example (Checking transactional deferreds)
import { Effect, TxDeferred } from "effect"
const program = Effect.gen(function*() {
const deferred = yield* TxDeferred.make<number>()
console.log(TxDeferred.isTxDeferred(deferred)) // true
console.log(TxDeferred.isTxDeferred("not a deferred")) // false
})
isTxDeferred = (u: unknownu: unknown): u: unknownu is 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<unknown, unknown> => import hasPropertyhasProperty(u: unknownu, const TypeId: "~effect/transactions/TxDeferred"TypeId)