Express Multiple res.json(); with middlewares - json

Question

I'm trying to build a stateless API using JWT. I have a middleware function in my Router which checks if the JWT has expired, if it has, a new Token with a new timestamp is generated on the fly.
I would like to pass the new token along with the response in the JSON Object. My current approach is like this, but it of course doesn't work:
router.use(function (req, res, next) {
// JWT Expired
// Generate new JWT
res.write(JSON.stringify({token: token});
next();
});
router.get('/securedRoute' function(req, res) {
// Fetch data
res.json({data: data});
});
:
// Output should be:
{token: 'erg34jlkgjre.3f4fknlj.34f3', data: ['sdfa', 'sdf']}
It would be nice to find a way, where I don't have to alter all of my existing code and check if there is a new token.
Thanks for your help!

Answer 1

One option would be to add the authorization token in the response header:
router.use((request, response, next) => {
response.setHeader('Token', token);
next();
});
router.get('/securedRoute', (request, response) => {
response.json({ data: data });
});
Alternatively, you could always add the token to the request and then conditionally add the request.token into all of your routes like the previous answer suggested. Unfortunately that would mean that you need to modify all of your routes.
As an alternative you could override the response.json method and manually inject the token if it exists. In doing so, you wouldn't need to modify any of your routes.
router.use((request, response, next) => {
request.token = token;
((proxied) => {
response.json = function (data) {
if (request && request.token) {
data.token = request.token;
}
return proxied.call(this, data);
};
})(response.json);
next();
});
router.get('/securedRoute', (request, response) => {
response.json({ data: data });
});
In the example above, the response.json method is overridden in the middleware. This is done by passing a reference to the old response.json method and then calling it after conditionally injecting the token into the payload.

Answer 2

The answer is assuming you want to achieve that in same method
Rather than writing the token in middleware do something like
(req,res,next)=>{
req.token = newToken;
next();
}
And in your route
res.json(req.token ? {token:req.token,data:data} : {data:data});