由于atob是浏览器端的，对于微信小程序不支持，导致模拟器【开发工具】显示正常，但真机异常解析失败问题，微信小程序原有的api，官方文档中也废弃了

解决方案：

调用：

const decodedString = base64_url_decode(res.data);
const jsonData = JSON.parse(decodedString);

weAtob  解密处理文件包 ：

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
var b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
var b64re = /^(?:[A-Za-z\d+\/]{4})*?(?:[A-Za-z\d+\/]{2}(?:==)?|[A-Za-z\d+\/]{3}=?)?$/;
exports.weBtoa = function (string) {string = String(string);var bitmap, a, b, c, result = "", i = 0, rest = string.length % 3;for (; i < string.length;) {if ((a = string.charCodeAt(i++)) > 255 ||(b = string.charCodeAt(i++)) > 255 ||(c = string.charCodeAt(i++)) > 255)throw new TypeError("Failed to execute 'btoa' on 'Window': The string to be encoded contains characters outside of the Latin1 range.");bitmap = (a << 16) | (b << 8) | c;result += b64.charAt(bitmap >> 18 & 63) + b64.charAt(bitmap >> 12 & 63) +b64.charAt(bitmap >> 6 & 63) + b64.charAt(bitmap & 63);}return rest ? result.slice(0, rest - 3) + "===".substring(rest) : result;
};
exports.weAtob = function (string) {string = String(string).replace(/[\t\n\f\r ]+/g, "");if (!b64re.test(string))throw new TypeError("Failed to execute 'atob' on 'Window': The string to be decoded is not correctly encoded.");string += "==".slice(2 - (string.length & 3));var bitmap, result = "", r1, r2, i = 0;for (; i < string.length;) {bitmap = b64.indexOf(string.charAt(i++)) << 18 | b64.indexOf(string.charAt(i++)) << 12 |(r1 = b64.indexOf(string.charAt(i++))) << 6 | (r2 = b64.indexOf(string.charAt(i++)));result += r1 === 64 ? String.fromCharCode(bitmap >> 16 & 255) :r2 === 64 ? String.fromCharCode(bitmap >> 16 & 255, bitmap >> 8 & 255) :String.fromCharCode(bitmap >> 16 & 255, bitmap >> 8 & 255, bitmap & 255);}return result;
};
function b64DecodeUnicode(str) {return decodeURIComponent(exports.weAtob(str).replace(/(.)/g, function (p) {var code = p.charCodeAt(0).toString(16).toUpperCase();if (code.length < 2) {code = "0" + code;}return "%" + code;}));
}
exports.base64_url_decode = function (str) {var output = str.replace(/-/g, "+").replace(/_/g, "/");switch (output.length % 4) {case 0:break;case 2:output += "==";break;case 3:output += "=";break;default:throw "Illegal base64url string!";}try {return b64DecodeUnicode(output);}catch (err) {return exports.weAtob(output);}
}
function weappJwtDecode(token, options) {if (typeof token !== "string") {throw ("Invalid token specified");}options = options || {};var pos = options.header === true ? 0 : 1;try {return JSON.parse(base64_url_decode(token.split(".")[pos]));}catch (e) {throw ("Invalid token specified: " + e.message);}
}
exports.default = weappJwtDecode;