export function genCode(len) {
    const chars = '123456789ABCDEFGHJKLMNPQRSTWXYZabcdefghijklmnopqrstuvwxyz';
    const charArr = chars.split('');
    let code = '';
    for (let i = 0; i < len; i++) {
      code += charArr[Math.floor(Math.random() * charArr.length)];
    }
    return code;
  }