function beautifyJSON(input) {
  var formatted = '';
  let spaces = 0;
  for (var i = 0; i < input.length; i++) {
    function closing(c) {
      return ['}', ']'].indexOf(c) >= 0;
    }
    function opening(c) {
      return ['{', '['].indexOf(c) >= 0;
    }
    let c = input[i];
    let previous = input[i-1];
    let next = input[i+1];

    let comma = c == ',' && !closing(previous);
    if (closing(c)) {
      formatted += "\n";
      spaces -= 2;
      if (spaces > 0) {
        formatted += " ".repeat(spaces);
      }
    }

    formatted += c

    if (opening(c)) {
      formatted += "\n";
      spaces += 2;
      if (spaces > 0) {
        formatted += " ".repeat(spaces)
      }
    } else if (c == ':' && next != ' ' && !closing(next)) {
      formatted += " ";
    } else if (c == ',') {
      formatted += "\n";
      if (spaces > 0) {
        formatted += " ".repeat(spaces);
      }
    }
  }
  return formatted;
}