如果你使用Node.JS 你可以通过以下方式使用本机Buffer模块:

const token = 'eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWUsImp0aSI6ImU3YjQ0Mjc4LTZlZDYtNDJlZC05MTZmLWFjZDQzNzhkM2U0YSIsImlhdCI6MTU5NTg3NzUxOCwiZXhwIjoxNTk1ODgxMTE4fQ.WXyDlDMMSJAjOFF9oAU9JrRHg2wio-WolWAkAaY3kg4';
const tokenDecodablePart = token.split('.')[1];
const decoded = Buffer.from(tokenDecodablePart, 'base64').toString();
console.log(decoded)

你就可以开始了:-)

如果你正在使用Typescript或普通JavaScript，这里有一个零依赖，准备复制粘贴到你的项目简单函数(基于@Rajan Maharjan的回答)。

This answer is particularly good, not only because it does not depend on any npm module, but also because it does not depend an any node.js built-in module (like Buffer) that some other solutions here are using and of course would fail in the browser (unless polyfilled, but there's no reason to do that in the first place). Additionally JSON.parse can fail at runtime and this version (especially in Typescript) will force handling of that. The JSDoc annotations will make future maintainers of your code thankful. :)

/**
 * Returns a JS object representation of a Javascript Web Token from its common encoded
 * string form.
 *
 * @template T the expected shape of the parsed token
 * @param {string} token a Javascript Web Token in base64 encoded, `.` separated form
 * @returns {(T | undefined)} an object-representation of the token
 * or undefined if parsing failed
 */
export function getParsedJwt<T extends object = { [k: string]: string | number }>(
  token: string,
): T | undefined {
  try {
    return JSON.parse(atob(token.split('.')[1]))
  } catch {
    return undefined
  }
}

为了完成，这里还有一个普通的javascript版本:

/**
 * Returns a JS object representation of a Javascript Web Token from its common encoded
 * string form.
 *
 * @param {string} token a Javascript Web Token in base64 encoded, `.` separated form
 * @returns {(object | undefined)} an object-representation of the token
 * or undefined if parsing failed
 */
export function getParsedJwt(token) {
  try {
    return JSON.parse(atob(token.split('.')[1]))
  } catch (error) {
    return undefined
  }
}

由于nodejs环境中没有“window”对象， 我们可以使用以下代码行:

let base64Url = token.split('.')[1]; // token you get
let base64 = base64Url.replace('-', '+').replace('_', '/');
let decodedData = JSON.parse(Buffer.from(base64, 'base64').toString('binary'));

它非常适合我。希望能有所帮助。

如果使用node.js 16或更高版本，可以使用内置的base64url编码器/解码器。

let payload = JSON.parse(Buffer.from(token.split(".")[1], "base64url"));

jwt的所有特性。IO不支持所有语言。在NodeJs中你可以使用

var decoded = jwt.decode(token);

在Node.js (TypeScript)中:

import { TextDecoder } from 'util';

function decode(jwt: string) {
    const { 0: encodedHeader, 1: encodedPayload, 2: signature, length } = jwt.split('.');

    if (length !== 3) {
        throw new TypeError('Invalid JWT');
    }

    const decode = (input: string): JSON => { return JSON.parse(new TextDecoder().decode(new Uint8Array(Buffer.from(input, 'base64')))); };

    return { header: decode(encodedHeader), payload: decode(encodedPayload), signature: signature };
}

与jose在GitHub上的panva，你可以使用最小的导入{解码为base64Decode}从'jose/util/base64url'和替换新的Uint8Array(Buffer.from(输入，'base64'))与base64Decode(输入)。这样代码就可以在浏览器和Node.js中正常工作。