CODEWITHSUNDEEP
node.jsexpress
TechnoCorner
TechnoCorner

Reputation: 5165

NodeJS response async

I've just started coding in NodeJS and I've got one question. I'm stuck in this place. I know that NodeJS is asyncronous but whenever i do a 'GET' for / I get a blank response.

    /* GET home page. */
    router.get('/', function(req, res, next) {
        var tenantID = 1; //Hardcoded TODO: Remove this value later
        var dwelltest = dwellTimeBucketModel.fetchFromDB(tenantID); 
          //I have a model in which I do all the DB calls (Cleaner to seperate?)
        res.json({dwell: dwelltest}); //Send response back
    }

Now, everytime I do this, my response gets sent out blank. (I know that this is due to async behavior). I am not sure how to get it working?

I've tried doing this:

var dwellResult = new Promise(function(resolve, reject){
     dwellTimeBucketModel.fetchFromDB(tenantID);
 });

dwellResult.then(function (result) {
    console.log(result);
    res.json({dwell: result})
}).catch(function (error) {
    console.error(error);
})

But the response is never sent. I am not sure what i am doing wrong?

Please advise if i'm following the right practice? (or standard?)

Thanks

Upvotes: 0

Views: 86

Answers (2)

Navoneel Talukdar
Navoneel Talukdar

Reputation: 4608

If you take a look at promise syntax here it is-

var p = new Promise(function(resolve, reject) {     
    // Do an async task async task and then...

    if(/* good condition */) {
        resolve('Success!');
    }
    else {
        reject('Failure!');
    }
});

p.then(function(response) { 
    /* do something with the result */
}).catch(function() {
    /* error :( */
})

Here are two more detailed articles for studying.

Upvotes: 1

jamesjaya
jamesjaya

Reputation: 665

Add resolve to the promise

var dwellResult = new Promise(function(resolve, reject){
   resolve(dwellTimeBucketModel.fetchFromDB(tenantID));
});

Upvotes: 3

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