js replace正则使用参数

let str = "abccbaaaddccbbcc";

let str1 = 'a',str2 = 'b;

// let reg = new RegExp(/(a|b)/,'g');

let reg = new RegExp(`(${str1}|${str2})`,'g');

let repStr = str.replace(reg, "");

console.log("repStr", repStr);