function compareText (x, y) {
  // we don't want to convert numbers to string, only accept string input
  if (!isString(x)) {
    throw new TypeError('Unexpected type of argument in function compareText ' +
      '(expected: string or Array or Matrix, actual: ' + typeOf(x) + ', index: 0)')
  }
  if (!isString(y)) {
    throw new TypeError('Unexpected type of argument in function compareText ' +
      '(expected: string or Array or Matrix, actual: ' + typeOf(y) + ', index: 1)')
  }

  return (x === y)
    ? 0
    : (x > y ? 1 : -1)
}
Compare two strings
@param {string} x
@param {string} y
@returns {number}