Package: effect
Module: MutableList
Prepends all elements from a ReadonlyArray to the beginning of the MutableList. This is an optimized version that can reuse the array when mutable=true.
When to use
Use when prepending a trusted array directly is worth the optimized path and you control whether the input may be reused.
Gotchas
When mutable=true, the input array may be modified internally. Only use mutable=true when you control the array lifecycle.
Example (Prepending arrays with optional mutation)
import { MutableList } from "effect"
const list = MutableList.make<number>()
MutableList.append(list, 4)
// Safe usage (default mutable=false)
const items = [1, 2, 3]
MutableList.prependAllUnsafe(list, items)
console.log(items) // [1, 2, 3] - unchanged
// Unsafe but efficient usage (mutable=true)
const mutableItems = [10, 20, 30]
MutableList.prependAllUnsafe(list, mutableItems, true)
// mutableItems may be modified internally for efficiency
console.log(MutableList.takeAll(list)) // [10, 20, 30, 1, 2, 3, 4]
Signature
declare const prependAllUnsafe: <A>(self: MutableList<A>, messages: ReadonlyArray<A>, mutable?: boolean) => void
Since v4.0.0