<A>(f: (a: A) => A): (self: Ref<A>) => Effect.Effect<A>
<A>(self: Ref<A>, f: (a: A) => A): Effect.Effect<A>Gets the current value of the Ref, updates it with the given function, and returns the previous value atomically.
When to use
Use to derive a new Ref value while returning the previous value.
Example (Updating and returning the previous value)
import { Effect, Ref } from "effect"
const program = Effect.gen(function*() {
const counter = yield* Ref.make(10)
// Get current value and update it atomically
const previous = yield* Ref.getAndUpdate(counter, (n) => n * 2)
console.log(previous) // 10
const current = yield* Ref.get(counter)
console.log(current) // 20
})export const const getAndUpdate: (<A>(
f: (a: A) => A
) => (self: Ref<A>) => Effect.Effect<A>) &
(<A>(
self: Ref<A>,
f: (a: A) => A
) => Effect.Effect<A>)
Gets the current value of the Ref, updates it with the given function, and returns the previous value atomically.
When to use
Use to derive a new Ref value while returning the previous value.
Example (Updating and returning the previous value)
import { Effect, Ref } from "effect"
const program = Effect.gen(function*() {
const counter = yield* Ref.make(10)
// Get current value and update it atomically
const previous = yield* Ref.getAndUpdate(counter, (n) => n * 2)
console.log(previous) // 10
const current = yield* Ref.get(counter)
console.log(current) // 20
})
getAndUpdate = import dualdual<
<function (type parameter) A in <A>(f: (a: A) => A): (self: Ref<A>) => Effect.Effect<A>A>(f: (a: A) => Af: (a: Aa: function (type parameter) A in <A>(f: (a: A) => A): (self: Ref<A>) => Effect.Effect<A>A) => function (type parameter) A in <A>(f: (a: A) => A): (self: Ref<A>) => Effect.Effect<A>A) => (self: Ref<A>(parameter) self: {
ref: MutableRef.MutableRef<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; <…;
}
interface Ref<in out A>A mutable reference that provides atomic read, write, and update operations.
When to use
Use to keep shared mutable state that is read and updated inside Effect
programs.
Details
A Ref is a thread-safe mutable reference type for shared state. It supports
simple read and write operations as well as atomic transformations.
Example (Reading and updating a ref)
import { Effect, Ref } from "effect"
const program = Effect.gen(function*() {
// Create a ref with initial value
const counter = yield* Ref.make(0)
// Read the current value
const value = yield* Ref.get(counter)
console.log(value) // 0
// Update the value atomically
yield* Ref.update(counter, (n) => n + 1)
// Read the updated value
const newValue = yield* Ref.get(counter)
console.log(newValue) // 1
})
The Ref namespace containing type definitions and utilities.
When to use
Use when referring to type members nested under the Ref namespace.
Ref<function (type parameter) A in <A>(f: (a: A) => A): (self: Ref<A>) => Effect.Effect<A>A>) => import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<function (type parameter) A in <A>(f: (a: A) => A): (self: Ref<A>) => Effect.Effect<A>A>,
<function (type parameter) A in <A>(self: Ref<A>, f: (a: A) => A): Effect.Effect<A>A>(self: Ref<A>(parameter) self: {
ref: MutableRef.MutableRef<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; <…;
}
interface Ref<in out A>A mutable reference that provides atomic read, write, and update operations.
When to use
Use to keep shared mutable state that is read and updated inside Effect
programs.
Details
A Ref is a thread-safe mutable reference type for shared state. It supports
simple read and write operations as well as atomic transformations.
Example (Reading and updating a ref)
import { Effect, Ref } from "effect"
const program = Effect.gen(function*() {
// Create a ref with initial value
const counter = yield* Ref.make(0)
// Read the current value
const value = yield* Ref.get(counter)
console.log(value) // 0
// Update the value atomically
yield* Ref.update(counter, (n) => n + 1)
// Read the updated value
const newValue = yield* Ref.get(counter)
console.log(newValue) // 1
})
The Ref namespace containing type definitions and utilities.
When to use
Use when referring to type members nested under the Ref namespace.
Ref<function (type parameter) A in <A>(self: Ref<A>, f: (a: A) => A): Effect.Effect<A>A>, f: (a: A) => Af: (a: Aa: function (type parameter) A in <A>(self: Ref<A>, f: (a: A) => A): Effect.Effect<A>A) => function (type parameter) A in <A>(self: Ref<A>, f: (a: A) => A): Effect.Effect<A>A) => import EffectEffect.type Effect.Effect = /*unresolved*/ anyEffect<function (type parameter) A in <A>(self: Ref<A>, f: (a: A) => A): Effect.Effect<A>A>
>(2, <function (type parameter) A in <A>(self: Ref<A>, f: (a: A) => A): anyA>(self: Ref<A>(parameter) self: {
ref: MutableRef.MutableRef<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; <…;
}
interface Ref<in out A>A mutable reference that provides atomic read, write, and update operations.
When to use
Use to keep shared mutable state that is read and updated inside Effect
programs.
Details
A Ref is a thread-safe mutable reference type for shared state. It supports
simple read and write operations as well as atomic transformations.
Example (Reading and updating a ref)
import { Effect, Ref } from "effect"
const program = Effect.gen(function*() {
// Create a ref with initial value
const counter = yield* Ref.make(0)
// Read the current value
const value = yield* Ref.get(counter)
console.log(value) // 0
// Update the value atomically
yield* Ref.update(counter, (n) => n + 1)
// Read the updated value
const newValue = yield* Ref.get(counter)
console.log(newValue) // 1
})
The Ref namespace containing type definitions and utilities.
When to use
Use when referring to type members nested under the Ref namespace.
Ref<function (type parameter) A in <A>(self: Ref<A>, f: (a: A) => A): anyA>, f: (a: A) => Af: (a: Aa: function (type parameter) A in <A>(self: Ref<A>, f: (a: A) => A): anyA) => function (type parameter) A in <A>(self: Ref<A>, f: (a: A) => A): anyA) =>
import EffectEffect.sync(() => {
const const current: anycurrent = self: Ref<A>(parameter) self: {
ref: MutableRef.MutableRef<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; <…;
}
Ref<in out A>.ref: MutableRef.MutableRef<A>(property) Ref<in out A>.ref: {
current: T;
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;
}
self: Ref<A>(parameter) self: {
ref: MutableRef.MutableRef<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; <…;
}
Ref<in out A>.ref: MutableRef.MutableRef<A>(property) Ref<in out A>.ref: {
current: T;
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;
}
f: (a: A) => Af(const current: anycurrent)
return const current: anycurrent
}))