/**
 * @description: utf16to8
 * @param {String} str
 * @return {String}
 */
export default function utf16to8(str) {
  var out, i, len, c;
  out = '';
  len = str.length;
  for (i = 0; i < len; i++) {
    c = str.charCodeAt(i);
    if (c >= 0x0001 && c <= 0x007f) {
      out += str.charAt(i);
    } else if (c > 0x07ff) {
      out += String.fromCharCode(0xe0 | ((c >> 12) & 0x0f));
      out += String.fromCharCode(0x80 | ((c >> 6) & 0x3f));
      out += String.fromCharCode(0x80 | ((c >> 0) & 0x3f));
    } else {
      out += String.fromCharCode(0xc0 | ((c >> 6) & 0x1f));
      out += String.fromCharCode(0x80 | ((c >> 0) & 0x3f));
    }
  }
  return out;
}