Get the return value of a single function within Promise

Question

I have the following snippet containing a Promise:

...
return Promise.all([postHTTP()])
 .then(function (results) {
   loginToken = results[0].data.token;
   console.log("token:" + loginToken);
   })
   .catch(error => {
   throw error;
});
...

And the function:

function postHTTP() {
    request.post({
        headers: { 'content-type': 'application/json' },
        url: 'http://localhost:55934/api/Token',
        body: { "email": "test@test.pt", "password": "test" },
        json: true
    }, function (error, response, body) {
        if (error) {
            throw error;
        }
        console.log("return test");
        return body.token;
    });

Altough the String "Return test" is printed, it gives me an error in the Promised above saying the following:

(node:15120) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): TypeError: Cannot read property 'token' of undefined

Can anyone help me finding a solution or the problem source for this?

Thanks in advance, Diogo Santos

Answer 1

The problem in your postHTTP function. When work with multi promise you have to pass array of promises into Promise.all , hence you function must look like this:

function postHTTP() {
  return new Promise(function (resolve, reject) {
    request.post({
        headers: { 'content-type': 'application/json' },
        url: 'http://localhost:55934/api/Token',
        body: { "email": "test@test.pt", "password": "test" },
        json: true
    }, function (error, response, body) {
        if (error) {
            return reject(error);
        }
        console.log("return test");
        return resolve(body.token);
    });
  });
}