CODEWITHSUNDEEP
node.jsjwtes6-promise
Martyn Ball
Martyn Ball

Reputation: 4895

Node promisify, await and return callback properties

is there a way I can convert the jsonwebtoken package verify method so it works in this way?

const { err, decoded } = await jwtPromise(post.journey_token, 'test');

I have managed to convert it to a promise, but this want's to use .then, however I don't want to do it this way. Currently err and decoded is undefined.

Here is the full code, can this be done?

import jwt from 'jsonwebtoken';
import util from 'util';

export const store: APIGatewayProxyHandler = async ({body}) => {
  const post = JSON.parse(body);
  const jwtPromise = util.promisify(jwt.verify);

  if (post.journey_token) {
    const { err, decoded } = await jwtPromise(post.journey_token, 'test');
    console.log(decoded, err);
  }

Upvotes: 0

Views: 229

Answers (3)

IAmDranged
IAmDranged

Reputation: 3020

You can convert any asynchronous function to return what you want. You can do so by wrapping it in another function which returns a promise, which instead of rejecting in case of an error always resolves to an object containing both an error and a result key.

function promisify(asyncFunction) {
    return function (...args_) {
        return new Promise(function (resolve, reject) {
            function cb(error, result) {
                resolve({ error, result })
            }
            var args = [
                ...args_,
                cb
            ]
            asyncFunction(...args)
        })
    }
}

Upvotes: 1

Lin Du
Lin Du

Reputation: 102527

Make your own verify function.

import jwt from 'jsonwebtoken';
import util from 'util';
const jwtPromise = util.promisify(jwt.verify);
const secret = 'shhhhh';
const wrongSecret = '123';

const token = jwt.sign({ foo: 'bar' }, secret);

export const store = async () => {
  const r = await verify(token, secret);
  console.log(r);
};

store();

function verify(token, secret) {
  return jwtPromise(token, secret)
    .then((decoded) => ({ err: null, decoded }))
    .catch((err) => ({ err, decoded: null }));
}

Verify correctly output:

{ err: null, decoded: { foo: 'bar', iat: 1619006803 } }

Verify failed output:

{
  err: JsonWebTokenError: invalid signature
      at /Users/dulin/workspace/github.com/mrdulin/expressjs-research/node_modules/jsonwebtoken/verify.js:133:19
      at getSecret (/Users/dulin/workspace/github.com/mrdulin/expressjs-research/node_modules/jsonwebtoken/verify.js:90:14)
      at module.exports (/Users/dulin/workspace/github.com/mrdulin/expressjs-research/node_modules/jsonwebtoken/verify.js:94:10)
      at internal/util.js:297:30
      at new Promise (<anonymous>)
      at internal/util.js:296:12
      at /Users/dulin/workspace/github.com/mrdulin/expressjs-research/src/stackoverflow/67195388/index.ts:10:19
      at Generator.next (<anonymous>)
      at /Users/dulin/workspace/github.com/mrdulin/expressjs-research/src/stackoverflow/67195388/index.ts:8:71
      at new Promise (<anonymous>),
  decoded: null
}

Upvotes: 1

Hamed Navvabian
Hamed Navvabian

Reputation: 792

err and decoded are in the third param as a callback passded to verify function:

jwt.verify(token, secretKey, (err, decoded) => {
    console.log(err, decoded);
    ...
});

Upvotes: -1

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