function mapToArray(map) {
  var index = -1,
      result = Array(map.size);

  map.forEach(function(value, key) {
    result[++index] = [key, value];
  });
  return result;
}
Converts `map` to its key-value pairs.

@private
@param {Object} map The map to convert.
@returns {Array} Returns the key-value pairs.