paren-match-recur.js

const Empty = Symbol();
const stateIdentity = 0;

const adjusters = {
    '(': 1,
    ')': -1
}

const getClosingParenPositionRec = (start, str) => {

    const inner = ([char = Empty, ...rest], state = stateIdentity, count = start) => {
        const nextState = state + (adjusters[char] || stateIdentity);

        return char === Empty || nextState === 0 
        ? count 
        : inner(rest, nextState, count + 1);
    }

    return inner(str.substring(start));
};