<K, V>(self: TxHashMap<K, V>): Effect.Effect<void>Removes all entries from the TxHashMap.
Details
This function mutates the original TxHashMap by clearing all key-value pairs. It does not return a new TxHashMap reference.
Example (Clearing all entries)
import { Effect, TxHashMap } from "effect"
const program = Effect.gen(function*() {
const sessionMap = yield* TxHashMap.make(
["session1", { userId: "alice", expires: "2024-01-01T12:00:00Z" }],
["session2", { userId: "bob", expires: "2024-01-01T13:00:00Z" }],
["session3", { userId: "charlie", expires: "2024-01-01T14:00:00Z" }]
)
// Check initial state
const initialSize = yield* TxHashMap.size(sessionMap)
console.log(initialSize) // 3
// Clear all sessions (e.g., during maintenance)
yield* TxHashMap.clear(sessionMap)
// Verify cleared
const finalSize = yield* TxHashMap.size(sessionMap)
console.log(finalSize) // 0
const isEmpty = yield* TxHashMap.isEmpty(sessionMap)
console.log(isEmpty) // true
})combinators
Source effect/TxHashMap.ts:5731 lines
export const const clear: <K, V>(
self: TxHashMap<K, V>
) => Effect.Effect<void>
Removes all entries from the TxHashMap.
Details
This function mutates the original TxHashMap by clearing all key-value pairs.
It does not return a new TxHashMap reference.
Example (Clearing all entries)
import { Effect, TxHashMap } from "effect"
const program = Effect.gen(function*() {
const sessionMap = yield* TxHashMap.make(
["session1", { userId: "alice", expires: "2024-01-01T12:00:00Z" }],
["session2", { userId: "bob", expires: "2024-01-01T13:00:00Z" }],
["session3", { userId: "charlie", expires: "2024-01-01T14:00:00Z" }]
)
// Check initial state
const initialSize = yield* TxHashMap.size(sessionMap)
console.log(initialSize) // 3
// Clear all sessions (e.g., during maintenance)
yield* TxHashMap.clear(sessionMap)
// Verify cleared
const finalSize = yield* TxHashMap.size(sessionMap)
console.log(finalSize) // 0
const isEmpty = yield* TxHashMap.isEmpty(sessionMap)
console.log(isEmpty) // true
})
clear = <function (type parameter) K in <K, V>(self: TxHashMap<K, V>): Effect.Effect<void>K, function (type parameter) V in <K, V>(self: TxHashMap<K, V>): Effect.Effect<void>V>(self: TxHashMap<K, V>(parameter) self: {
ref: TxRef.TxRef<HashMap.HashMap<K, V>>;
toString: () => string;
toJSON: () => unknown;
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; <…;
}
interface TxHashMap<in out K, in out V>A TxHashMap is a transactional hash map data structure that provides atomic operations
on key-value pairs within Effect transactions. It uses an immutable HashMap internally
with TxRef for transactional semantics, ensuring all operations are performed atomically.
Example (Using transactional hash maps)
import { Effect, TxHashMap } from "effect"
const program = Effect.gen(function*() {
// Create a transactional hash map
const txMap = yield* TxHashMap.make(["user1", "Alice"], ["user2", "Bob"])
// Single operations are automatically transactional
yield* TxHashMap.set(txMap, "user3", "Charlie")
const user = yield* TxHashMap.get(txMap, "user1")
console.log(user) // Option.some("Alice")
// Multi-step atomic operations
yield* Effect.tx(
Effect.gen(function*() {
const currentUser = yield* TxHashMap.get(txMap, "user1")
if (currentUser._tag === "Some") {
yield* TxHashMap.set(txMap, "user1", currentUser.value + "_updated")
yield* TxHashMap.remove(txMap, "user2")
}
})
)
const size = yield* TxHashMap.size(txMap)
console.log(size) // 2
})
The TxHashMap namespace contains type-level utilities and helper types
for working with TxHashMap instances.
Example (Reusing extracted TxHashMap types)
import { Effect, TxHashMap } from "effect"
const program = Effect.gen(function*() {
// Create a transactional inventory map
const inventory = yield* TxHashMap.make(
["laptop", { stock: 5, price: 999 }],
["mouse", { stock: 20, price: 29 }]
)
// Extract types for reuse
type ProductId = TxHashMap.TxHashMap.Key<typeof inventory> // string
type Product = TxHashMap.TxHashMap.Value<typeof inventory> // { stock: number, price: number }
type InventoryEntry = TxHashMap.TxHashMap.Entry<typeof inventory> // [string, Product]
// Use extracted types in functions
const updateStock = (id: ProductId, newStock: number) =>
TxHashMap.modify(
inventory,
id,
(product) => ({ ...product, stock: newStock })
)
yield* updateStock("laptop", 3)
})
TxHashMap<function (type parameter) K in <K, V>(self: TxHashMap<K, V>): Effect.Effect<void>K, function (type parameter) V in <K, V>(self: TxHashMap<K, V>): Effect.Effect<void>V>): import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<void> => import TxRefTxRef.const set: {
<A>(value: A): (
self: TxRef<A>
) => Effect.Effect<void>
<A>(
self: TxRef<A>,
value: A
): Effect.Effect<void>
}
self: TxHashMap<K, V>(parameter) self: {
ref: TxRef.TxRef<HashMap.HashMap<K, V>>;
toString: () => string;
toJSON: () => unknown;
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; <…;
}
TxHashMap<in out K, in out V>.ref: TxRef.TxRef<HashMap.HashMap<K, V>>(property) TxHashMap<in out K, in out V>.ref: {
version: number;
pending: Map<unknown, () => void>;
value: A;
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; <…;
}
import HashMapHashMap.empty<function (type parameter) K in <K, V>(self: TxHashMap<K, V>): Effect.Effect<void>K, function (type parameter) V in <K, V>(self: TxHashMap<K, V>): Effect.Effect<void>V>())