Having trouble with JsonWebToken; JsonWebToken Error: JWT must be provided

Question

I'm building my first SPA project with Vue.

I decided to go with NodeJS for the back-end, however, I'm having a headache building the login function with the JsonWebToken.

I had wrote some codes to see how JWT works and when I tried to see how JWT gets verified, server gave me an error.

JsonWebTokenError: jwt must be provided
at Object.module.exports [as verify] (c:\dir\node_modules\jsonwebtoken\verify.js:39:17)
at c:\projects\practice\demo\back\server.js:34:17

Below is the code for my server.js

This is the code for importing the stuff.

const express = require('express');
const jwt = require('jsonwebtoken');
const bodyParser = require('body-parser');
const api = express();

api.use(bodyParser.json());
api.use(bodyParser.urlencoded({ extended: true }));

This is for the API for issuing JWT.

api.post('/secure', function (req, res) {
const token = jwt.sign({ user: {id:1, name:'ME!', role: 'average'} }, 'dsfklgj');
console.log(token);
res.json({jwt: token});
});

This is the API for checking JWT.

api.post('/check/post', function (req, res) {
const token = req.body.jwt;
const x = jwt.verify(token, 'dsfklgj', function (err, decoded) {
if (err) throw err;
console.log(decoded);
});
if (x != true) {
res.json({ auth: false });
}else {
res.json({ auth: true });
}
});

Answer 1

jwt must be provided

This error happens when the coming token is null or empty.

Answer 2

It may be you have not defined jwt in specific file or it is null or empty. Therefore you are getting an error. I just test your code and it works for me. It may be that you are not sending jwt token into post request correctly.

const express = require('express');
const jwt = require('jsonwebtoken');
const bodyParser = require('body-parser');
const http = require('http');
const api = express();

api.use(bodyParser.json());
api.use(bodyParser.urlencoded({ extended: true }));

api.post('/secure', function(req, res) {
    const token = jwt.sign({ user: { id: 1, name: 'ME!', role: 'average' } }, 'dsfklgj');
    console.log(token);
    res.json({ jwt: token });
});


api.post('/check/post', function(req, res) {
    const token = req.body.jwt;
    console.log('token: ' + token);
    const x = jwt.verify(token, 'dsfklgj', function(err, decoded) {
        if (err) throw err;
        console.log(decoded);
    });
    console.log(x);
    if (x != true) {
        res.json({ auth: false });
    } else {
        res.json({ auth: true });
    }
});

api.set('port', 3000);
var server = http.createServer(api);
server.listen(api.get('port'), function() {
    console.log("Express server listening on port " + api.get('port'));
});

BTW there is no way to test it like like this const x = jwt.verify(token, 'dsfklgj', function (err, decoded) {. Either write it in Sync way or check condition in async callback function. In your case, x will be undefined and no guarantee when it will run.