<K, V>(predicate: (value: V, key: K) => boolean): (
self: TxHashMap<K, V>
) => Effect.Effect<Option.Option<[K, V]>>
<K, V>(
self: TxHashMap<K, V>,
predicate: (value: V, key: K) => boolean
): Effect.Effect<Option.Option<[K, V]>>Finds the first entry in the TxHashMap that matches the given predicate. Returns the key-value pair as a tuple wrapped in an Option.
Example (Finding the first matching entry)
import { Effect, TxHashMap } from "effect"
const program = Effect.gen(function*() {
// Create a task priority map
const tasks = yield* TxHashMap.make(
["task1", { priority: 1, assignee: "alice", completed: false }],
["task2", { priority: 3, assignee: "bob", completed: true }],
["task3", { priority: 2, assignee: "alice", completed: false }]
)
// Find first high-priority incomplete task
const highPriorityTask = yield* TxHashMap.findFirst(
tasks,
(task) => task.priority >= 2 && !task.completed
)
if (highPriorityTask._tag === "Some") {
const [taskId, task] = highPriorityTask.value
console.log(`Found task: ${taskId}, priority: ${task.priority}`)
// "Found task: task3, priority: 2"
}
// Find first task assigned to specific user
const aliceTask = yield* tasks.pipe(
TxHashMap.findFirst((task) => task.assignee === "alice")
)
if (aliceTask._tag === "Some") {
console.log(`Alice's task: ${aliceTask.value[0]}`)
}
})combinators
Source effect/TxHashMap.ts:174516 lines
export const const findFirst: {
<K, V>(
predicate: (value: V, key: K) => boolean
): (
self: TxHashMap<K, V>
) => Effect.Effect<Option.Option<[K, V]>>
<K, V>(
self: TxHashMap<K, V>,
predicate: (value: V, key: K) => boolean
): Effect.Effect<Option.Option<[K, V]>>
}
Finds the first entry in the TxHashMap that matches the given predicate.
Returns the key-value pair as a tuple wrapped in an Option.
Example (Finding the first matching entry)
import { Effect, TxHashMap } from "effect"
const program = Effect.gen(function*() {
// Create a task priority map
const tasks = yield* TxHashMap.make(
["task1", { priority: 1, assignee: "alice", completed: false }],
["task2", { priority: 3, assignee: "bob", completed: true }],
["task3", { priority: 2, assignee: "alice", completed: false }]
)
// Find first high-priority incomplete task
const highPriorityTask = yield* TxHashMap.findFirst(
tasks,
(task) => task.priority >= 2 && !task.completed
)
if (highPriorityTask._tag === "Some") {
const [taskId, task] = highPriorityTask.value
console.log(`Found task: ${taskId}, priority: ${task.priority}`)
// "Found task: task3, priority: 2"
}
// Find first task assigned to specific user
const aliceTask = yield* tasks.pipe(
TxHashMap.findFirst((task) => task.assignee === "alice")
)
if (aliceTask._tag === "Some") {
console.log(`Alice's task: ${aliceTask.value[0]}`)
}
})
findFirst: {
<function (type parameter) K in <K, V>(predicate: (value: V, key: K) => boolean): (self: TxHashMap<K, V>) => Effect.Effect<Option.Option<[K, V]>>K, function (type parameter) V in <K, V>(predicate: (value: V, key: K) => boolean): (self: TxHashMap<K, V>) => Effect.Effect<Option.Option<[K, V]>>V>(
predicate: (value: V, key: K) => booleanpredicate: (value: Vvalue: function (type parameter) V in <K, V>(predicate: (value: V, key: K) => boolean): (self: TxHashMap<K, V>) => Effect.Effect<Option.Option<[K, V]>>V, key: Kkey: function (type parameter) K in <K, V>(predicate: (value: V, key: K) => boolean): (self: TxHashMap<K, V>) => Effect.Effect<Option.Option<[K, V]>>K) => boolean
): (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>(predicate: (value: V, key: K) => boolean): (self: TxHashMap<K, V>) => Effect.Effect<Option.Option<[K, V]>>K, function (type parameter) V in <K, V>(predicate: (value: V, key: K) => boolean): (self: TxHashMap<K, V>) => Effect.Effect<Option.Option<[K, V]>>V>) => import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<import OptionOption.type Option.Option = /*unresolved*/ anyOption<[function (type parameter) K in <K, V>(predicate: (value: V, key: K) => boolean): (self: TxHashMap<K, V>) => Effect.Effect<Option.Option<[K, V]>>K, function (type parameter) V in <K, V>(predicate: (value: V, key: K) => boolean): (self: TxHashMap<K, V>) => Effect.Effect<Option.Option<[K, V]>>V]>>
<function (type parameter) K in <K, V>(self: TxHashMap<K, V>, predicate: (value: V, key: K) => boolean): Effect.Effect<Option.Option<[K, V]>>K, function (type parameter) V in <K, V>(self: TxHashMap<K, V>, predicate: (value: V, key: K) => boolean): Effect.Effect<Option.Option<[K, V]>>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>, predicate: (value: V, key: K) => boolean): Effect.Effect<Option.Option<[K, V]>>K, function (type parameter) V in <K, V>(self: TxHashMap<K, V>, predicate: (value: V, key: K) => boolean): Effect.Effect<Option.Option<[K, V]>>V>,
predicate: (value: V, key: K) => booleanpredicate: (value: Vvalue: function (type parameter) V in <K, V>(self: TxHashMap<K, V>, predicate: (value: V, key: K) => boolean): Effect.Effect<Option.Option<[K, V]>>V, key: Kkey: function (type parameter) K in <K, V>(self: TxHashMap<K, V>, predicate: (value: V, key: K) => boolean): Effect.Effect<Option.Option<[K, V]>>K) => boolean
): import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<import OptionOption.type Option.Option = /*unresolved*/ anyOption<[function (type parameter) K in <K, V>(self: TxHashMap<K, V>, predicate: (value: V, key: K) => boolean): Effect.Effect<Option.Option<[K, V]>>K, function (type parameter) V in <K, V>(self: TxHashMap<K, V>, predicate: (value: V, key: K) => boolean): Effect.Effect<Option.Option<[K, V]>>V]>>
} = import dualdual(
2,
<function (type parameter) K in <K, V>(self: TxHashMap<K, V>, predicate: (value: V, key: K) => boolean): Effect.Effect<Option.Option<[K, V]>>K, function (type parameter) V in <K, V>(self: TxHashMap<K, V>, predicate: (value: V, key: K) => boolean): Effect.Effect<Option.Option<[K, V]>>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>, predicate: (value: V, key: K) => boolean): Effect.Effect<Option.Option<[K, V]>>K, function (type parameter) V in <K, V>(self: TxHashMap<K, V>, predicate: (value: V, key: K) => boolean): Effect.Effect<Option.Option<[K, V]>>V>,
predicate: (value: V, key: K) => booleanpredicate: (value: Vvalue: function (type parameter) V in <K, V>(self: TxHashMap<K, V>, predicate: (value: V, key: K) => boolean): Effect.Effect<Option.Option<[K, V]>>V, key: Kkey: function (type parameter) K in <K, V>(self: TxHashMap<K, V>, predicate: (value: V, key: K) => boolean): Effect.Effect<Option.Option<[K, V]>>K) => boolean
): import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<import OptionOption.type Option.Option = /*unresolved*/ anyOption<[function (type parameter) K in <K, V>(self: TxHashMap<K, V>, predicate: (value: V, key: K) => boolean): Effect.Effect<Option.Option<[K, V]>>K, function (type parameter) V in <K, V>(self: TxHashMap<K, V>, predicate: (value: V, key: K) => boolean): Effect.Effect<Option.Option<[K, V]>>V]>> =>
import TxRefTxRef.const get: <A>(
self: TxRef<A>
) => Effect.Effect<A>
Reads the current value of the TxRef.
When to use
Use to read the current value of a TxRef.
Example (Reading transactional references)
import { Effect, TxRef } from "effect"
const program = Effect.gen(function*() {
const counter = yield* TxRef.make(42)
// Read the value within a transaction
const value = yield* Effect.tx(
TxRef.get(counter)
)
console.log(value) // 42
})
get(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 EffectEffect.map((map: HashMap.HashMap<K, V>(parameter) map: {
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; <…;
toString: () => string;
toJSON: () => unknown;
}
import HashMapHashMap.findFirst(map: HashMap.HashMap<K, V>(parameter) map: {
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; <…;
toString: () => string;
toJSON: () => unknown;
}
predicate: (value: V, key: K) => booleanpredicate)))
)