CODEWITHSUNDEEP
node.jsmongodbexpress
test1500
test1500

Reputation: 65

Async Await mongoDb always returns undefined

this is my async function

   async duplicate_email(db, email) {
        await db.collection("users").findOne({ 'email': email }, function(findErr, result) {
            console.log(findErr)
            if (!result) {
                return false
            } else {
                return true
            }
        });
    }

I call it like this from another file :

 middleware.duplicate_email(db, "[email protected]").then((answer) => {
        console.log(answer)
    });

answer always returns undefined, while result is populated.

Upvotes: 1

Views: 517

Answers (3)

silencedogood
silencedogood

Reputation: 3299

You should utilize the async/await promise syntax by setting the mongo call equal to a variable. Something like this:

async duplicate_email(db, email) {

   let myResults;
   try {
     myResults = await db.collection("users").findOne({ 'email': email });
   } catch (err) {
      console.log(err);
   }
   return myResults ? true : false;
 }

You can then consume the promise returned by duplicate_email

middleware.duplicate_email(db, "[email protected]").then((answer) => {
    console.log(answer)
});

That's the beauty of using async / await. You no longer need the callbacks. However, for error trapping, you'll need the try catch block.

Upvotes: 0

Ilijanovic
Ilijanovic

Reputation: 14904

Here is an short solution

Just return the result and invert it twice. You will get either true or false

async duplicate_email(db, email) {
    try {
       return !!(await db.collection("users").findOne({ 'email': email }))
    }catch(err) {
       console.log(err)
    }
}

Upvotes: 0

Kuldeep Mishra
Kuldeep Mishra

Reputation: 4040

async duplicate_email(db, email) {
   let availableEmail =  await db.collection("users").findOne({ 'email': email }) 
       
        if (!availableEmail) {
            return false
        } else {
            return true
        }
    });
}

if you are using async function then dont use callback.

Upvotes: 0

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