js解析富文本符号，网上找了一下教程，大概都是这样写的：

str = str.replace(/∀/g, '∀');

str = str.replace(/∂/g, '∂');

str = str.replace(/&exists;/g, '∃');

str = str.replace(/∅/g, '∅');

str = str.replace(/∇/g, '∇');

str = str.replace(/∈/g, '∈');

只需转换常用的特殊符号的话，这样写似乎没什么问题。但是我百度到一个有700多个特殊符号的对照表(有首字母大写小写两种的，找不到相关链接了)。把700多个替换语句写在同一个函数里，微信小程序编译的时候会报错：

Error:file:

component/WxParse/wxParse/wxDiscode.js Maximum call stack size exceeded

所以显然不能每个符号调用一次替换是不科学的。代替的方法是改成用replace的回调函数。

var SupplementCode = [{c:"↖",e:"↖"},{c:"↗","e":"↗"},{c:"↘","e":"↘"},{c:"↙","e":"↙"},{c:"©","e":"©"},{c:"®","e":"®"},{c:"@","e":"@"},{c:"✓","e":"✓"},{c:"$","e":"$"},{c:"¢","e":"¢"},{c:"£","e":"£"},{c:"¥","e":"¥"},{c:"+","e":"+"},{c:"×","e":"×"}];

var SupplementCodeMatch = `(↖)|(↗)|(↘)|(↙)|(©)|(®)|(@)|(✓)|($)|(¢)|(£)|(¥)|(+)|(×)`;

var str = str.replace(new RegExp(SupplementCodeMatch,'ig'), function(s){

let entry = SupplementCode.find(a=>a.c==s);

return entry?entry.e:s;

});

SupplementCode存编码和实体的对应关系，SupplementCodeMatch用于生成正则表达式。在回调函数中查找对应的值并替换。

扩展其他实体符号只需要把SupplementCode和SupplementCodeMatch扩充即可。