It is to my understanding that callback functions are asynchronous and cannot return a value like regular functions. Upon reading about promises, I thought I grasped a good understanding about them, that they are basically an enhanced version of callbacks that allows returning a value like asynchronous function. In my getConnections method, I am attempting to call the find() function on my database through mongoose, and I am attempting to grab this array of objects and send it to the views.

var test =  new Promise((resolve, reject) => {
        Database.find().then(list => {
            resolve(list);

        }).catch(err=> {
            return reject(err);
        })

        })
console.log(test)

When I attempt to log to the console outside of the promise function, I get Promise { _U: 0, _V: 0, _W: null, _X: null }

I don't think this is functioning correctly, and I thought I utilized promises correctly. Could anyone point me in the right direction on how to return this array of objects outside of the callback function?

It is to my understanding that callback functions are asynchronous and cannot return a value like regular functions. Upon reading about promises, I thought I grasped a good understanding about them, that they are basically an enhanced version of callbacks that allows returning a value like asynchronous function. In my getConnections method, I am attempting to call the find() function on my database through mongoose, and I am attempting to grab this array of objects and send it to the views.

var test =  new Promise((resolve, reject) => {
        Database.find().then(list => {
            resolve(list);

        }).catch(err=> {
            return reject(err);
        })

        })
console.log(test)

When I attempt to log to the console outside of the promise function, I get Promise { _U: 0, _V: 0, _W: null, _X: null }

I don't think this is functioning correctly, and I thought I utilized promises correctly. Could anyone point me in the right direction on how to return this array of objects outside of the callback function?

• javascript
• node.js
• mongodb
• mongoose

• 1 Does this answer your question? How do I return the response from an asynchronous call? – Anurag Srivastava Commented Apr 17, 2020 at 22:31
• 1 Try this instead: test.then(x=> console.log(x));. then is the normal mechanism to get the result of the promise once it resolves. – David784 Commented Apr 17, 2020 at 22:50
• Well I get the console log but I want to access this variable outside the document and send it to views. – Calamity Commented Apr 17, 2020 at 23:13
• rethink your code ... think like this ... asynchrony can not be made synchronous, because I'm writing javascript, not developing a time machine :D – Jaromanda X Commented Apr 18, 2020 at 0:12
• send it to views sounds something you could wrap into then(). – tevemadar Commented Apr 18, 2020 at 8:15

4 Answers 4

You can simply add await before the promise declaration. i.e.

var test = await new Promise...

The thing is that when you write a function like this:

const getData = async () => { const response = await fetch(someUrl, {}, {}); return response;}

Then you also need to await that function when you call it. Like this:

const setData = async () => { const dataToSet = await getData(); }

let test =  new Promise((resolve, reject) => {
        Database.find().then(list => {
            resolve(list);

        }).catch(err=> {
            return reject(err);
        })

        })

test
.then(result=>console.log(result))

Should solve your problem.

    var someValue;
    var test =  await new Promise((resolve, reject) => {
        Database.find().then(list => {
           resolve(list);

         }).catch(err=> {
           return reject(err);
       })

    }).then(res => {
      someValue=res;
    })

   console.log(someValue);