var empty, extend;

empty = function() {
  return [[Infinity, -Infinity], [Infinity, -Infinity]];
};

extend = function(a, b) {
  a[0][0] = Math.min(a[0][0], b[0][0]);
  a[0][1] = Math.max(a[0][1], b[0][1]);
  a[1][0] = Math.min(a[1][0], b[1][0]);
  a[1][1] = Math.max(a[1][1], b[1][1]);
  return a;
};

module.exports = {
  empty: empty,
  extend: extend
};
