Minimum Remove to Make Valid Parentheses

export function minRemoveToMakeValid(s: string): string {
  const chars = [...s];
  const stack: number[] = [];
 
  chars.forEach((char, i) => {
    if (char === '(') {
      stack.push(i);
    } else if (char === ')') {
      if (0 < stack.length) {
        stack.pop();
      } else {
        chars[i] = '';
      }
    }
  });
 
  while (0 < stack.length) {
    chars[stack.pop()!] = '';
  }
 
  return chars.join('');
}