将普通字符和Unicode编码、HTML实体编码的互转整合成两个函数：

1. var str2unicode = (str,hex=true) => {
2.     let u = hex ? [...str].map(str => '\u' + str.codePointAt(0).toString(16)).join('') : [...str].map(str => '&#' + str.codePointAt(0) + ';').join('');
3.     return u;
4. }
5. 
   
6. var unicode2str = (str,hex=true) => {
7.     let outstr = '';
8.     str = str.replaceAll(/(\u)|(\U)|(u+(s?))|(U+s?)|(0X)|(&#)|(&)/g,'0x');
9.     var ar = str.split('0x');
10.     ar.forEach(a => {
11.         let num = parseInt(a, hex ? 16 : 10);
12.         outstr += num >= 0 && num <= 0x10FFFF ? String.fromCodePoint(num) : a;
13.     });
14.     return outstr;
15. };