variable / @typed/fx/RefHashMap

modifyAt

Modify the value at a key using an Option-based update function.

Package version
2.0.0-beta.7
Category
State updates
Since
1.18.0

Import

import { modifyAt } from "@typed/fx/RefHashMap";

Signatures

export declare const modifyAt: {
    <K, V>(key: K, f: HashMap.HashMap.UpdateFn<V>): <E, R>(ref: RefHashMap<K, V, E, R>) => Effect.Effect<HashMap.HashMap<K, V>, E, R>;
    <K, V, E, R>(ref: RefHashMap<K, V, E, R>, key: K, f: HashMap.HashMap.UpdateFn<V>): Effect.Effect<HashMap.HashMap<K, V>, E, R>;
};

Why

Keeps modify at atomic with respect to competing RefSubject writes instead of splitting the read and replacement into separate effects.

Ownership and lifetime

Running modify at performs one serialized hash map transition and resolves with its committed value. It acquires no resource; failures and services remain those of the source ref.

Other public imports

These import paths expose the same declaration. Each page retains its own public name and signature.

Source