Contrived functional solution to a classic coding interview question.

match-parens.ts

const values = [
    null, 'abc', '',
    '()', '[]',
    '([])', '[()]',
    '([]())', '[[]()]',
    '([][]())', '[[[()()]()]()]',
    '(abc)', '[]def', 'ijk[]()',
    '[a(b)c]', 'x[a(b)c]y',
    'x[a(b)c]', '[a(b)c]y',
    '[([[]])]', '[][(]',
    ']()', '([)]',
    ']', '[',
];

const matches = {
    '(': ')',
    '[': ']',
}

if (!values || values.length === 0) return true;

const scores = values.map((value) => {
    if (!value || value.length === 0) return true;

    const stack = [];

    return [...value]
        .map((char) => {
            Object.keys(matches).some(c => c === char)
                && stack.push(char);

            return !(Object.values(matches).some(c => c === char)
                && matches[stack.pop()] !== char);
        })
        .reduce((previous, current) =>
            previous && current,
            true
        ) && stack.length === 0;
});

const result = Object.fromEntries(values.map((_, i) => [values[i], scores[i]]));
console.log(result);