<K, V>(self: TxHashMap<K, V>): Effect.Effect<boolean>Checks whether the TxHashMap is non-empty.
Example (Checking for a non-empty map)
import { Effect, TxHashMap } from "effect"
const program = Effect.gen(function*() {
const inventory = yield* TxHashMap.make(["laptop", 5])
const hasItems = yield* TxHashMap.isNonEmpty(inventory)
console.log(hasItems) // true
// Clear inventory
yield* TxHashMap.clear(inventory)
const stillHasItems = yield* TxHashMap.isNonEmpty(inventory)
console.log(stillHasItems) // false
})combinators
Source effect/TxHashMap.ts:6732 lines
export const const isNonEmpty: <K, V>(
self: TxHashMap<K, V>
) => Effect.Effect<boolean>
Checks whether the TxHashMap is non-empty.
Example (Checking for a non-empty map)
import { Effect, TxHashMap } from "effect"
const program = Effect.gen(function*() {
const inventory = yield* TxHashMap.make(["laptop", 5])
const hasItems = yield* TxHashMap.isNonEmpty(inventory)
console.log(hasItems) // true
// Clear inventory
yield* TxHashMap.clear(inventory)
const stillHasItems = yield* TxHashMap.isNonEmpty(inventory)
console.log(stillHasItems) // false
})
isNonEmpty = <function (type parameter) K in <K, V>(self: TxHashMap<K, V>): Effect.Effect<boolean>K, function (type parameter) V in <K, V>(self: TxHashMap<K, V>): Effect.Effect<boolean>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<boolean>K, function (type parameter) V in <K, V>(self: TxHashMap<K, V>): Effect.Effect<boolean>V>): import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<boolean> =>
import EffectEffect.map(const isEmpty: <K, V>(
self: TxHashMap<K, V>
) => Effect.Effect<boolean>
Checks whether the TxHashMap is empty.
Example (Checking for an empty map)
import { Effect, TxHashMap } from "effect"
const program = Effect.gen(function*() {
// Start with empty map
const cache = yield* TxHashMap.empty<string, any>()
const empty = yield* TxHashMap.isEmpty(cache)
console.log(empty) // true
// Add an item
yield* TxHashMap.set(cache, "key1", "value1")
const stillEmpty = yield* TxHashMap.isEmpty(cache)
console.log(stillEmpty) // false
// Clear and check again
yield* TxHashMap.clear(cache)
const emptyAgain = yield* TxHashMap.isEmpty(cache)
console.log(emptyAgain) // true
})
isEmpty(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; <…;
}
empty: anyempty) => !empty: anyempty)