Node Js variable does not showing result

Question

I am trying to display database value in a variable but does not return any value.

below is the code.

var mssql = require('mssql');
var resultData='';
function getStyleData(){    
  var msSqlSettings = {
     server      : 'localhost',
     port        : '51663',
     user        : 'sa',
     password    : 'admin1234',
     database    : 'ComWriter.Temp002'
};  
mssql.close();  
mssql.connect(msSqlSettings, function (err ) { 
    if (err) {
        throw (err);
    }   
    var getQuery = "SELECT [Title] FROM [dbo].[Templates] " ;   
    var request = new mssql.Request();          
    request.query(getQuery, function (err, rows) {          
        //console.log(rows);
        mssql.close();
        resultData = rows;
    });
}); 
   return resultData;
}




var getFunction = getStyleData();

   console.log(getFunction);

Possible duplicate of [How do I return the response from an asynchronous call?](https://stackoverflow.com/questions/14220321/how-do-i-return-the-response-from-an-asynchronous-call) — JJJ, Jul 01 '17 at 14:27

Lena Kaplan · Answer 1 · 2017-07-01T15:15:59.223

It looks that you return resultData right after you call connect, maybe before the connection even established, and before query returned the result. Node is asynchronous so it doesn't wait for the results, try to console.log the rows inside the request.query call.

mssql.connect(msSqlSettings, function (err ) { 
    if (err) {
        throw (err);
    }   
    var getQuery = "SELECT [Title] FROM [dbo].[Templates] " ;   
    var request = new mssql.Request();          
    request.query(getQuery, function (err, rows) {          
        //console.log(rows);
        mssql.close();
        console.log(JSON.stringify(rows));
    });
});

You can pass in a callback to your getStyleData() and pass this callback to request.query() this way the rows will be returned asyncrounsly when the query will complete. This way you can pass in callback that wants to use the result.

getStyleDate(done){
    // your code ...
    mssql.connect(msSqlSettings, function (err ) { 
        if (err) {
            throw (err);
        }   
        var getQuery = "SELECT [Title] FROM [dbo].[Templates] " ;   
        var request = new mssql.Request();          
        request.query(getQuery, done);
    }); 

}

I have tried to return inside the callback but it does not return any value. — Sushil Kumar, Jul 01 '17 at 14:35

RIYAJ KHAN · Answer 2 · 2017-07-01T14:59:48.563

0

You can not return data from callback(asynchronous) in synchronous way

Need to refactor the code.

function getStyleData(callback) {
    var msSqlSettings = ..//;
    mssql.connect(msSqlSettings, function (err) {
        if (err) {
            callback("error message", null);
        }
        //query
        request.query(getQuery, function (err, rows) {

            resultData = rows;
            if (err) {
                callback("error message", null);
            } else {
                callback(null, resultDat);
            }
        });
    });
}



getStyleData(function (err, data) {

    if (err) {
        console.log("error");
    }

    console.log(data);
});

edited Jul 01 '17 at 14:59

answered Jul 01 '17 at 14:54

RIYAJ KHAN

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Hello , I want to return value not console log. Can you tell me how to return value in a variable? – Sushil Kumar Jul 03 '17 at 04:57
frrom getStyleData? – RIYAJ KHAN Jul 03 '17 at 04:59

Node Js variable does not showing result

2 Answers2