Async function returning existing array as undefined

Content Index :

Async function returning existing array as undefined
Inside async function, returning value from a callback function returns Promise(undefined)
function keeps returning undefined array using Async Await
Async function is returning undefined
Async function returning undefined instead of data
Async function returning undefined in NodeJS

Async function returning existing array as undefined

Tag : javascript , By : Felix Almeida

Date : January 11 2021, 03:32 PM

wish of those help I have an async function inside my class that does execute like it is supposed, but its return value is undefined when I call it. Executing console.log(array) just before the return line "return array" does work , you have to return something from the async function,

// wait for response
return await fetch("https://api.purecore.io/rest/1/session/get/?key=" + this.key, { method: "GET" }).then(function (response) {

class Core {
    constructor(key) {
        this.key = key;
    }
    async getSessions() {
        var finalresponse = []
        try {
            // wait for response
            return await fetch("https://api.purecore.io/rest/1/session/get/?key=" + this.key, { method: "GET" }).then(function (response) {
                return response.json();
            }).then(function (jsonresponse) {
                // looks for errors
                if (jsonresponse.error != null) {
                    throw new Error("PureCore returned an error: " + jsonresponse.error + " -> " + jsonresponse.msg)
                } else {
                    // adds the sessions to the response
                    jsonresponse.forEach(player => {
                        finalresponse.push(new CoreSession(player["mojang_username"], player["mojang_uuid"], player["core_id"], player["verified"]))
                    });
                    console.log(finalresponse) // returns array list
                    return finalresponse; // returns undefined
                }
            });
        } catch (e) {
            throw new Error("Error while getting the response for 'https://api.purecore.io/rest/1/session/get/?key=" + this.key + "' -> " + e.message)
        }
    }
}

class CoreSession {
    constructor(username, uuid, core_uuid, verified) {
        this.username = username;
        this.uuid = uuid;
        this.core_uuid = core_uuid;
        this.verified = verified;
    }
}

// testing:
sessions = new Core("731b59d106ea5acd0a385958d8e0f18b4b74b741f28f6efa43ed4a273a42d6f9").getSessions().then(function (value) {
    console.log(value)
}, function (reason) {
    console.log(reason)
});

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Async function returning existing array as undefined , Async , function , returning , existing , array , undefined ,

Inside async function, returning value from a callback function returns Promise(undefined)

Tag : javascript , By : Florian D.

Date : March 29 2020, 07:55 AM

will be helpful for those in need I'm new to asynchronous programming, I'm facing issue similar to this question, in this question suggested approach uses callbacks but I'm trying to do it using Promises and async-await functions. I get undefined in the console. Here's my example. what am I missing? , make your query function return a Promise

function query(sql, args) {
    return new Promise(function (resolve , reject) {
        this.connection.query(sql, args, (err, rows) => {
            if (err)
                reject(err);
            else
                resolve(rows)
        });
    });
}


//calling the function here 
query("select 1")
.then((row) => console.log("Rows",row)) // Rows undefined
.catch((e) => console.log(e));

function keeps returning undefined array using Async Await

Tag : javascript , By : Ari

Date : March 29 2020, 07:55 AM

it helps some times The way to return the promise is not by adding new Promise (which is an anti-pattern in this case), but to get the promise that jQuery already has for you:

    return $.getJSON(url, function(data) {
//  ^^^^^^
       // .......
    }).promise();
//    ^^^^^^^^^^

    return $.getJSON(url).then(function(data) {
//  ^^^^^^               ^^^^^^
       // .......
       return levels;
    });

Async function is returning undefined

Tag : javascript , By : Helpful Dude

Date : March 29 2020, 07:55 AM

it should still fix some issue You do not return anything from your openChat function, so that function resolves to undefined.
You have to write:

export async function openChat(otherPersonId) {
  const user = firebase.auth().currentUser
  const userId = user.uid

  return firestore // here you need to return the returned promise of the promise chain
    .collection('users')
    .doc(userId)
    .get()
    /* .... */
}

async getChatId(userId) {
  let chatId = await openChat(userId)
  console.log('chatId', chatId) //UNDEFINED
  return chatId
}

async requestChat(userId) {
  let result = await this.getChatId(userId)
  console.log('result', result) //UNDEFINED
}

Async function returning undefined instead of data

Tag : javascript , By : Ari

Date : March 29 2020, 07:55 AM

With these it helps I'm doing requests to my API server to authenticate a user, that's not the problem. The problem is that I don't know why my async function doesn't return anything, and I get an error because the data that I want from this function is undefined. , Your Async function must return the last promise:

return fetch('http://api.myapi.cc/authenticate', ...);

var x = await fetch('http://api.myapi.cc/authenticate', ...);
// do something with x and...
return x;

function a() {
    return functionReturningPromise().then(function (result) {
        return result + 1;
    });
}

async function b() {
    return (await functionReturningPromise()) + 1;
}

Async function returning undefined in NodeJS

Tag : javascript , By : Raghaw

Date : March 29 2020, 07:55 AM

this one helps. You don't need to use callback function when you use async/await
Try this code:

obtenerCategoria = async(category) => {
    const categoriaDB = await Categoria.findOne({ descripcion: category });
    if (!categoriaDB) {
        return res.status(400).json({
            ok: false,
            msg: 'Categoria no encontrada'
        })
    }
    console.log(categoriaDB); // Works fine here
    return categoriaDB
}