JavaScript: Check whether an 'input' is a string or not

is_string = function(input) {
  if (Object.prototype.toString.call(input) === '[object String]')
    return true;
  else
    return false;   
    };
console.log(is_string('w3resource'));
console.log(is_string([1, 2, 4, 0]));

 Output:

true
false