<K, V>(key: K, f: (value: Option.Option<V>) => Option.Option<V>): (
self: TxHashMap<K, V>
) => Effect.Effect<void>
<K, V>(
self: TxHashMap<K, V>,
key: K,
f: (value: Option.Option<V>) => Option.Option<V>
): Effect.Effect<void>Updates the value for the specified key using an Option-based update function.
Details
This function mutates the original TxHashMap by updating, adding, or removing the key-value pair based on the function result. It does not return a new TxHashMap reference.
Example (Updating values with Option)
import { Effect, TxHashMap } from "effect"
const program = Effect.gen(function*() {
const storage = yield* TxHashMap.make<string, string | number>([
"file1.txt",
"content1"
], ["access_count", 0])
// Increment existing counter
yield* TxHashMap.modifyAt(storage, "access_count", (current) =>
current._tag === "Some" && typeof current.value === "number"
? { ...current, value: current.value + 1 }
: current
)
const count1 = yield* TxHashMap.get(storage, "access_count")
console.log(count1) // Option.some(1)
// Increment existing counter again
yield* TxHashMap.modifyAt(storage, "access_count", (current) =>
current._tag === "Some" && typeof current.value === "number"
? { ...current, value: current.value + 1 }
: current
)
const count2 = yield* TxHashMap.get(storage, "access_count")
console.log(count2) // Option.some(2)
// Update an existing string entry
yield* TxHashMap.modifyAt(storage, "file1.txt", (current) =>
current._tag === "Some" && typeof current.value === "string"
? { ...current, value: `${current.value}.bak` }
: current
)
const backup = yield* TxHashMap.get(storage, "file1.txt")
console.log(backup) // Option.some("content1.bak")
})combinators
Source effect/TxHashMap.ts:79929 lines
export const const modifyAt: {
<K, V>(
key: K,
f: (
value: Option.Option<V>
) => Option.Option<V>
): (
self: TxHashMap<K, V>
) => Effect.Effect<void>
<K, V>(
self: TxHashMap<K, V>,
key: K,
f: (
value: Option.Option<V>
) => Option.Option<V>
): Effect.Effect<void>
}
Updates the value for the specified key using an Option-based update function.
Details
This function mutates the original TxHashMap by updating, adding, or removing
the key-value pair based on the function result. It does not return a new
TxHashMap reference.
Example (Updating values with Option)
import { Effect, TxHashMap } from "effect"
const program = Effect.gen(function*() {
const storage = yield* TxHashMap.make<string, string | number>([
"file1.txt",
"content1"
], ["access_count", 0])
// Increment existing counter
yield* TxHashMap.modifyAt(storage, "access_count", (current) =>
current._tag === "Some" && typeof current.value === "number"
? { ...current, value: current.value + 1 }
: current
)
const count1 = yield* TxHashMap.get(storage, "access_count")
console.log(count1) // Option.some(1)
// Increment existing counter again
yield* TxHashMap.modifyAt(storage, "access_count", (current) =>
current._tag === "Some" && typeof current.value === "number"
? { ...current, value: current.value + 1 }
: current
)
const count2 = yield* TxHashMap.get(storage, "access_count")
console.log(count2) // Option.some(2)
// Update an existing string entry
yield* TxHashMap.modifyAt(storage, "file1.txt", (current) =>
current._tag === "Some" && typeof current.value === "string"
? { ...current, value: `${current.value}.bak` }
: current
)
const backup = yield* TxHashMap.get(storage, "file1.txt")
console.log(backup) // Option.some("content1.bak")
})
modifyAt: {
<function (type parameter) K in <K, V>(key: K, f: (value: Option.Option<V>) => Option.Option<V>): (self: TxHashMap<K, V>) => Effect.Effect<void>K, function (type parameter) V in <K, V>(key: K, f: (value: Option.Option<V>) => Option.Option<V>): (self: TxHashMap<K, V>) => Effect.Effect<void>V>(
key: Kkey: function (type parameter) K in <K, V>(key: K, f: (value: Option.Option<V>) => Option.Option<V>): (self: TxHashMap<K, V>) => Effect.Effect<void>K,
f: (
value: Option.Option<V>
) => Option.Option<V>
value: Option.Option<V>value: import OptionOption.type Option.Option = /*unresolved*/ anyOption<function (type parameter) V in <K, V>(key: K, f: (value: Option.Option<V>) => Option.Option<V>): (self: TxHashMap<K, V>) => Effect.Effect<void>V>) => import OptionOption.type Option.Option = /*unresolved*/ anyOption<function (type parameter) V in <K, V>(key: K, f: (value: Option.Option<V>) => Option.Option<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>(key: K, f: (value: Option.Option<V>) => Option.Option<V>): (self: TxHashMap<K, V>) => Effect.Effect<void>K, function (type parameter) V in <K, V>(key: K, f: (value: Option.Option<V>) => Option.Option<V>): (self: TxHashMap<K, V>) => Effect.Effect<void>V>) => import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<void>
<function (type parameter) K in <K, V>(self: TxHashMap<K, V>, key: K, f: (value: Option.Option<V>) => Option.Option<V>): Effect.Effect<void>K, function (type parameter) V in <K, V>(self: TxHashMap<K, V>, key: K, f: (value: Option.Option<V>) => Option.Option<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>, key: K, f: (value: Option.Option<V>) => Option.Option<V>): Effect.Effect<void>K, function (type parameter) V in <K, V>(self: TxHashMap<K, V>, key: K, f: (value: Option.Option<V>) => Option.Option<V>): Effect.Effect<void>V>,
key: Kkey: function (type parameter) K in <K, V>(self: TxHashMap<K, V>, key: K, f: (value: Option.Option<V>) => Option.Option<V>): Effect.Effect<void>K,
f: (
value: Option.Option<V>
) => Option.Option<V>
value: Option.Option<V>value: import OptionOption.type Option.Option = /*unresolved*/ anyOption<function (type parameter) V in <K, V>(self: TxHashMap<K, V>, key: K, f: (value: Option.Option<V>) => Option.Option<V>): Effect.Effect<void>V>) => import OptionOption.type Option.Option = /*unresolved*/ anyOption<function (type parameter) V in <K, V>(self: TxHashMap<K, V>, key: K, f: (value: Option.Option<V>) => Option.Option<V>): Effect.Effect<void>V>
): import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<void>
} = import dualdual(
3,
<function (type parameter) K in <K, V>(self: TxHashMap<K, V>, key: K, f: (value: Option.Option<V>) => Option.Option<V>): Effect.Effect<void>K, function (type parameter) V in <K, V>(self: TxHashMap<K, V>, key: K, f: (value: Option.Option<V>) => Option.Option<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>, key: K, f: (value: Option.Option<V>) => Option.Option<V>): Effect.Effect<void>K, function (type parameter) V in <K, V>(self: TxHashMap<K, V>, key: K, f: (value: Option.Option<V>) => Option.Option<V>): Effect.Effect<void>V>,
key: Kkey: function (type parameter) K in <K, V>(self: TxHashMap<K, V>, key: K, f: (value: Option.Option<V>) => Option.Option<V>): Effect.Effect<void>K,
f: (
value: Option.Option<V>
) => Option.Option<V>
value: Option.Option<V>value: import OptionOption.type Option.Option = /*unresolved*/ anyOption<function (type parameter) V in <K, V>(self: TxHashMap<K, V>, key: K, f: (value: Option.Option<V>) => Option.Option<V>): Effect.Effect<void>V>) => import OptionOption.type Option.Option = /*unresolved*/ anyOption<function (type parameter) V in <K, V>(self: TxHashMap<K, V>, key: K, f: (value: Option.Option<V>) => Option.Option<V>): Effect.Effect<void>V>
): import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<void> =>
import EffectEffect.gen(function*() {
const const currentMap: HashMap.HashMap<K, V>const currentMap: {
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 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; <…;
}
const currentValue: Option.Option<V>currentValue = import HashMapHashMap.get(const currentMap: HashMap.HashMap<K, V>const currentMap: {
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;
}
key: Kkey)
const const newValue: Option.Option<V>newValue = f: (
value: Option.Option<V>
) => Option.Option<V>
const currentValue: Option.Option<V>currentValue)
if (import OptionOption.isSome(const newValue: Option.Option<V>newValue)) {
yield* 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.set(const currentMap: HashMap.HashMap<K, V>const currentMap: {
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;
}
key: Kkey, const newValue: Option.Some<V>const newValue: {
_tag: "Some";
_op: "Some";
value: A;
valueOrUndefined: 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; <…;
toString: () => string;
toJSON: () => unknown;
}
import OptionOption.isSome(const currentValue: Option.Option<V>currentValue)) {
yield* 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.remove(const currentMap: HashMap.HashMap<K, V>const currentMap: {
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;
}
key: Kkey))
}
}).pipe(import EffectEffect.tx)
)