(self: MutableRef<number>): numberDecrements a numeric MutableRef by 1 and returns the new value.
When to use
Use to decrement a numeric MutableRef and immediately read the updated
value.
Example (Decrementing and reading refs)
import { MutableRef } from "effect"
const counter = MutableRef.make(5)
// Decrement and get the new value
const newValue = MutableRef.decrementAndGet(counter)
console.log(newValue) // 4
console.log(MutableRef.get(counter)) // 4
// Use in expressions
const lives = MutableRef.make(3)
console.log(`Lives remaining: ${MutableRef.decrementAndGet(lives)}`) // "Lives remaining: 2"
// Conditional logic based on decremented value
const attempts = MutableRef.make(3)
while (MutableRef.decrementAndGet(attempts) >= 0) {
console.log("Retrying...")
// retry logic
}export const const decrementAndGet: (
self: MutableRef<number>
) => number
Decrements a numeric MutableRef by 1 and returns the new value.
When to use
Use to decrement a numeric MutableRef and immediately read the updated
value.
Example (Decrementing and reading refs)
import { MutableRef } from "effect"
const counter = MutableRef.make(5)
// Decrement and get the new value
const newValue = MutableRef.decrementAndGet(counter)
console.log(newValue) // 4
console.log(MutableRef.get(counter)) // 4
// Use in expressions
const lives = MutableRef.make(3)
console.log(`Lives remaining: ${MutableRef.decrementAndGet(lives)}`) // "Lives remaining: 2"
// Conditional logic based on decremented value
const attempts = MutableRef.make(3)
while (MutableRef.decrementAndGet(attempts) >= 0) {
console.log("Retrying...")
// retry logic
}
decrementAndGet = (self: MutableRef<number>(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<number>): number => const updateAndGet: {
<T>(f: (value: T) => T): (
self: MutableRef<T>
) => T
<T>(self: MutableRef<T>, f: (value: T) => T): T
}
self: MutableRef<number>(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;
}
n: numbern) => n: numbern - 1)