import {useEffect, useState} from 'react';

export default class StateMapper<T> {
    private getFun: () => T;
    private cbs: Set<Function> = new Set([]);
    constructor(getFun: () => T) {
        this.getFun = getFun;
    }

    notify = () => {
        this.cbs.forEach(_ => _?.());
    };

    useMappedState = () => {
        const [_state, _setState] = useState<T>(this.getFun);
        const updateState = () => {
            _setState(this.getFun());
        };
        useEffect(() => {
            this.cbs.add(updateState);
            return () => {
                this.cbs.delete(updateState);
            };
        }, []);
        return _state;
    };
}