微信小程序使用 jwt-decode 库出现 atob is not defined 错误

修复 jwt-decode 在生产环境报错 atob is not defined 错误问题

错误信息：

@file 解决直接使用 jwt-decode.js 出现以下错误问题

- [decodeToken error] <InvalidTokenError: Invalid token specified: invalid base64 for part #2 (atob is not defined)>
  InvalidTokenError: Invalid token specified: invalid base64 for part #2 (atob is not defined)
  at module.exports.o.jwtDecode (https://usr/appservice.app.js:629:2289)
  at v (https://usr/appservice.app.js:755:1016)
  at https://usr/appservice.app.js:755:3794
  at s (https://usr/appservice.app.js:575:738)
  at Generator.<anonymous> (https://usr/appservice.app.js:575:2075)
  at Generator.next (https://usr/appservice.app.js:575:1101)
  at asyncGeneratorStep (https://usr/appservice.app.js:537:58)
  at c (https://usr/appservice.app.js:537:277)
  at https://usr/appservice.app.js:537:370
  at new Promise (<anonymous>)

解决方案：

1. 创建 jwt-decode.js，内容如下

/**
 * @file 解决直接使用jwt-decode.js 出现以下错误问题
 * [decodeToken error] <InvalidTokenError: Invalid token specified: invalid base64 for part #2 (atob is not defined)>
InvalidTokenError: Invalid token specified: invalid base64 for part #2 (atob is not defined)
    at module.exports.o.jwtDecode (https://usr/appservice.app.js:629:2289)
    at v (https://usr/appservice.app.js:755:1016)
    at https://usr/appservice.app.js:755:3794
    at s (https://usr/appservice.app.js:575:738)
    at Generator.<anonymous> (https://usr/appservice.app.js:575:2075)
    at Generator.next (https://usr/appservice.app.js:575:1101)
    at asyncGeneratorStep (https://usr/appservice.app.js:537:58)
    at c (https://usr/appservice.app.js:537:277)
    at https://usr/appservice.app.js:537:370
    at new Promise (<anonymous>)
 */

// Base64解码函数
function base64Decode(input) {
  const chars =
    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
  let str = "";

  // 处理 Base64 非法字符
  input = String(input).replace(/=+$/, "");

  if (input.length % 4 === 1) {
    throw new Error(
      "'atob' failed: The string to be decoded is not correctly encoded."
    );
  }

  for (
    let bc = 0, bs = 0, buffer, i = 0;
    (buffer = input.charAt(i++));
    ~buffer && ((bs = bc % 4 ? bs * 64 + buffer : buffer), bc++ % 4)
      ? (str += String.fromCharCode(255 & (bs >> ((-2 * bc) & 6))))
      : 0
  ) {
    buffer = chars.indexOf(buffer);
  }

  return str;
}

// JWT解码函数
export const jwtDecode = (token) => {
  const [header, payload, signature] = token.split(".");

  if (!header || !payload || !signature) {
    throw new Error("Invalid token");
  }

  // 使用自定义的 Base64 解码函数解码 payload
  const decodedPayload = base64Decode(
    payload.replace(/-/g, "+").replace(/_/g, "/")
  );
  return JSON.parse(decodedPayload);
};

2. 引入，使用我们自己的 jwt-decode.js 替代 jwt-decode

// import {jwtDecode} from 'jwt-decode';
import { jwtDecode } from "./jwt-decode.js";

const decodeToken = (token) => {
  try {
    return jwtDecode(token);
  } catch (error) {
    console.error("[decodeToken error token]", token);
    console.error("[decodeToken error]", error);
    return null;
  }
};

const userToken = "your token";

const decodedUserToken = decodeToken(userToken);