decode-jwt-token.md

Decoding JWT Token

function parseJwt(token) {
    var [, base64Url] = token.split('.');
    var base64 = base64Url.replace(/-/g, '+').replace(/_/g, '/');
    var decodedBase64 = atob(base64);
    var encodedPayload = decodedBase64.split('').map(c => {
        return '%' + ('00' + c.charCodeAt(0).toString(16)).slice(-2);
    }).join('');
    var payload = decodeURIComponent(encodedPayload);

    try {
        return JSON.parse(payload);
    } catch (e) {
        return payload;
    }
}

atob() in Node.js

...
var decodedBase64 = Buffer.from(base64, 'base64').toString();
...