Generate JWT in Expo

jwt.js

import HmacSHA256 from 'crypto-js/hmac-sha256';
import Base64 from 'crypto-js/enc-base64';
import Utf8 from 'crypto-js/enc-utf8';

const header = {
  alg: 'HS256',
  typ: 'JWT'
};

const body = { foo: 'bar' };

const jsonHeader = JSON.stringify(header);
const jsonBody = JSON.stringify(body);

const headerEncoded = Base64.stringify(Utf8.parse(jsonHeader));
const bodyEncoded = Base64.stringify(Utf8.parse(jsonBody));

const key = 'shh';
const signature = HmacSHA256(`${headerEncoded}.${bodyEncoded}`, key);
const signatureEncoded = signature.toString(Base64);

const token = `${headerEncoded}.${bodyEncoded}.${signatureEncoded}`;

Just passing through, you should also consider replacing the symbols that are unsafe to use in a URL: ' +', '/', and '='. Otherwise, your final encoded signature might be different.

Hi @HeavenMin, that’s a good point.

Do you have any examples where this has been an issue?

I just added a new test to the repo to try this out and so far the library seems to encode/decode as expected.

Cheers,
Blake