nested 2

function verify (t) {
  var brackets = [
    ['(', ')'],
    ['{', '}'],
    ['[', ']']
  ];

  var nestingProblem = false;
  for (let i = 0; i < brackets.length; i++) {
    nestingProblem = (t.split(brackets[i][0]).length !== t.split(brackets[i][1]).length)
    if (nestingProblem)
      break;
  }

  return (nestingProblem) ? -1 : 1;
}