export declare type SetStateAction<Value> = Value | ((prev: Value) => Value);
export declare type Getter = <Value>(atom: Atom<Value>) => Value;
export declare type Setter = <Value, Update>(atom: WritableAtom<Value, Update>, update: Update) => void;
export declare type Atom<Value> = {
    key: string | number;
    init?: Value;
    read: (get: Getter) => Value | Promise<Value>;
};
export declare type WritableAtom<Value, Update> = Atom<Value> & {
    write: (get: Getter, set: Setter, update: Update) => void | Promise<void>;
};
export declare type PrimitiveAtom<Value> = WritableAtom<Value, SetStateAction<Value>>;
export declare type AnyAtom = Atom<unknown>;
export declare type AnyWritableAtom = WritableAtom<unknown, unknown>;