<T>(f: (value: T) => T): (self: MutableRef<T>) => T
<T>(self: MutableRef<T>, f: (value: T) => T): TUpdates the MutableRef with the result of applying a function to its current value, and returns the previous value.
When to use
Use to transform the current MutableRef value while keeping the previous
value.
Example (Reading before updating)
import { MutableRef } from "effect"
const counter = MutableRef.make(5)
// Increment and get the old value
const oldValue = MutableRef.getAndUpdate(counter, (n) => n + 1)
console.log(oldValue) // 5
console.log(MutableRef.get(counter)) // 6
// Double the value and get the previous one
const previous = MutableRef.getAndUpdate(counter, (n) => n * 2)
console.log(previous) // 6
console.log(MutableRef.get(counter)) // 12
// Transform string and get old value
const message = MutableRef.make("hello")
const oldMessage = MutableRef.getAndUpdate(message, (s) => s.toUpperCase())
console.log(oldMessage) // "hello"
console.log(MutableRef.get(message)) // "HELLO"
// Pipe-able version
const addOne = MutableRef.getAndUpdate((n: number) => n + 1)
const result = addOne(counter)
console.log(result) // Previous value before increment
// Useful for implementing atomic operations
const list = MutableRef.make<Array<number>>([1, 2, 3])
const oldList = MutableRef.getAndUpdate(list, (arr) => [...arr, 4])
console.log(oldList) // [1, 2, 3]
console.log(MutableRef.get(list)) // [1, 2, 3, 4]general
Source effect/MutableRef.ts:4647 lines
export const const getAndUpdate: {
<T>(f: (value: T) => T): (
self: MutableRef<T>
) => T
<T>(self: MutableRef<T>, f: (value: T) => T): T
}
Updates the MutableRef with the result of applying a function to its current value,
and returns the previous value.
When to use
Use to transform the current MutableRef value while keeping the previous
value.
Example (Reading before updating)
import { MutableRef } from "effect"
const counter = MutableRef.make(5)
// Increment and get the old value
const oldValue = MutableRef.getAndUpdate(counter, (n) => n + 1)
console.log(oldValue) // 5
console.log(MutableRef.get(counter)) // 6
// Double the value and get the previous one
const previous = MutableRef.getAndUpdate(counter, (n) => n * 2)
console.log(previous) // 6
console.log(MutableRef.get(counter)) // 12
// Transform string and get old value
const message = MutableRef.make("hello")
const oldMessage = MutableRef.getAndUpdate(message, (s) => s.toUpperCase())
console.log(oldMessage) // "hello"
console.log(MutableRef.get(message)) // "HELLO"
// Pipe-able version
const addOne = MutableRef.getAndUpdate((n: number) => n + 1)
const result = addOne(counter)
console.log(result) // Previous value before increment
// Useful for implementing atomic operations
const list = MutableRef.make<Array<number>>([1, 2, 3])
const oldList = MutableRef.getAndUpdate(list, (arr) => [...arr, 4])
console.log(oldList) // [1, 2, 3]
console.log(MutableRef.get(list)) // [1, 2, 3, 4]
getAndUpdate: {
<function (type parameter) T in <T>(f: (value: T) => T): (self: MutableRef<T>) => TT>(f: (value: T) => Tf: (value: Tvalue: function (type parameter) T in <T>(f: (value: T) => T): (self: MutableRef<T>) => TT) => function (type parameter) T in <T>(f: (value: T) => T): (self: MutableRef<T>) => TT): (self: MutableRef<T>(parameter) self: {
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;
}
interface MutableRef<out T>A synchronous mutable reference that stores a current value.
When to use
Use to keep local mutable state in a stable, pipeable reference.
Details
Read or write the value directly through .current, or use the MutableRef
helpers for pipeable updates such as get, set, update, and
compareAndSet. All operations mutate the same reference in place.
Example (Creating and updating refs)
import { MutableRef } from "effect"
// Create a mutable reference
const ref: MutableRef.MutableRef<number> = MutableRef.make(42)
// Read the current value
console.log(ref.current) // 42
console.log(MutableRef.get(ref)) // 42
// Update the value
ref.current = 100
console.log(MutableRef.get(ref)) // 100
// Use with complex types
interface Config {
timeout: number
retries: number
}
const config: MutableRef.MutableRef<Config> = MutableRef.make({
timeout: 5000,
retries: 3
})
// Update through the interface
config.current = { timeout: 10000, retries: 5 }
console.log(config.current.timeout) // 10000
MutableRef<function (type parameter) T in <T>(f: (value: T) => T): (self: MutableRef<T>) => TT>) => function (type parameter) T in <T>(f: (value: T) => T): (self: MutableRef<T>) => TT
<function (type parameter) T in <T>(self: MutableRef<T>, f: (value: T) => T): TT>(self: MutableRef<T>(parameter) self: {
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;
}
interface MutableRef<out T>A synchronous mutable reference that stores a current value.
When to use
Use to keep local mutable state in a stable, pipeable reference.
Details
Read or write the value directly through .current, or use the MutableRef
helpers for pipeable updates such as get, set, update, and
compareAndSet. All operations mutate the same reference in place.
Example (Creating and updating refs)
import { MutableRef } from "effect"
// Create a mutable reference
const ref: MutableRef.MutableRef<number> = MutableRef.make(42)
// Read the current value
console.log(ref.current) // 42
console.log(MutableRef.get(ref)) // 42
// Update the value
ref.current = 100
console.log(MutableRef.get(ref)) // 100
// Use with complex types
interface Config {
timeout: number
retries: number
}
const config: MutableRef.MutableRef<Config> = MutableRef.make({
timeout: 5000,
retries: 3
})
// Update through the interface
config.current = { timeout: 10000, retries: 5 }
console.log(config.current.timeout) // 10000
MutableRef<function (type parameter) T in <T>(self: MutableRef<T>, f: (value: T) => T): TT>, f: (value: T) => Tf: (value: Tvalue: function (type parameter) T in <T>(self: MutableRef<T>, f: (value: T) => T): TT) => function (type parameter) T in <T>(self: MutableRef<T>, f: (value: T) => T): TT): function (type parameter) T in <T>(self: MutableRef<T>, f: (value: T) => T): TT
} = import DualDual.dual<
<function (type parameter) T in <T>(f: (value: T) => T): (self: MutableRef<T>) => TT>(f: (value: T) => Tf: (value: Tvalue: function (type parameter) T in <T>(f: (value: T) => T): (self: MutableRef<T>) => TT) => function (type parameter) T in <T>(f: (value: T) => T): (self: MutableRef<T>) => TT) => (self: MutableRef<T>(parameter) self: {
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;
}
interface MutableRef<out T>A synchronous mutable reference that stores a current value.
When to use
Use to keep local mutable state in a stable, pipeable reference.
Details
Read or write the value directly through .current, or use the MutableRef
helpers for pipeable updates such as get, set, update, and
compareAndSet. All operations mutate the same reference in place.
Example (Creating and updating refs)
import { MutableRef } from "effect"
// Create a mutable reference
const ref: MutableRef.MutableRef<number> = MutableRef.make(42)
// Read the current value
console.log(ref.current) // 42
console.log(MutableRef.get(ref)) // 42
// Update the value
ref.current = 100
console.log(MutableRef.get(ref)) // 100
// Use with complex types
interface Config {
timeout: number
retries: number
}
const config: MutableRef.MutableRef<Config> = MutableRef.make({
timeout: 5000,
retries: 3
})
// Update through the interface
config.current = { timeout: 10000, retries: 5 }
console.log(config.current.timeout) // 10000
MutableRef<function (type parameter) T in <T>(f: (value: T) => T): (self: MutableRef<T>) => TT>) => function (type parameter) T in <T>(f: (value: T) => T): (self: MutableRef<T>) => TT,
<function (type parameter) T in <T>(self: MutableRef<T>, f: (value: T) => T): TT>(self: MutableRef<T>(parameter) self: {
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;
}
interface MutableRef<out T>A synchronous mutable reference that stores a current value.
When to use
Use to keep local mutable state in a stable, pipeable reference.
Details
Read or write the value directly through .current, or use the MutableRef
helpers for pipeable updates such as get, set, update, and
compareAndSet. All operations mutate the same reference in place.
Example (Creating and updating refs)
import { MutableRef } from "effect"
// Create a mutable reference
const ref: MutableRef.MutableRef<number> = MutableRef.make(42)
// Read the current value
console.log(ref.current) // 42
console.log(MutableRef.get(ref)) // 42
// Update the value
ref.current = 100
console.log(MutableRef.get(ref)) // 100
// Use with complex types
interface Config {
timeout: number
retries: number
}
const config: MutableRef.MutableRef<Config> = MutableRef.make({
timeout: 5000,
retries: 3
})
// Update through the interface
config.current = { timeout: 10000, retries: 5 }
console.log(config.current.timeout) // 10000
MutableRef<function (type parameter) T in <T>(self: MutableRef<T>, f: (value: T) => T): TT>, f: (value: T) => Tf: (value: Tvalue: function (type parameter) T in <T>(self: MutableRef<T>, f: (value: T) => T): TT) => function (type parameter) T in <T>(self: MutableRef<T>, f: (value: T) => T): TT) => function (type parameter) T in <T>(self: MutableRef<T>, f: (value: T) => T): TT
>(2, (self: MutableRef<T>(parameter) self: {
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: anyf) => const getAndSet: {
<T>(value: T): (self: MutableRef<T>) => T
<T>(self: MutableRef<T>, value: T): T
}
self: MutableRef<T>(parameter) self: {
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: anyf(const get: <T>(self: MutableRef<T>) => TGets the current value of the MutableRef.
When to use
Use to read the current MutableRef value without mutating it.
Example (Reading current values)
import { MutableRef } from "effect"
const ref = MutableRef.make("hello")
console.log(MutableRef.get(ref)) // "hello"
MutableRef.set(ref, "world")
console.log(MutableRef.get(ref)) // "world"
// Reading complex objects
const config = MutableRef.make({ port: 3000, host: "localhost" })
const currentConfig = MutableRef.get(config)
console.log(currentConfig.port) // 3000
// Multiple reads return the same value
const value1 = MutableRef.get(ref)
const value2 = MutableRef.get(ref)
console.log(value1 === value2) // true
get(self: MutableRef<T>(parameter) self: {
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;
}
Referenced by 2 symbols