Can't return any value while connecting Redshift from Node JS

Question

The following code connected to Redshift database but returning an empty response even the response will be displayed in the console.log, why?

index.js

   
const config = {
  user: 'user',
  database: 'database',
  password: 'password',
  port: port,
  host: 'hostname',
};
var response = [];
console.log('Before Connection');
exports.handler =  function index(event, context, callback) {
  var redshiftClient = new Redshift(config, {rawConnection:true});
    redshiftClient.connect(function(err){
    console.log('After Connection');
    if(err) throw err;
    else{
      redshiftClient.query('SELECT * FROM customer', {raw: true}, function(err, data){
        if(err) throw err;
        else{
            response = data;
            console.log(data);
            redshiftClient.close();
            return response;
            
        }
         
      });
    }
  });
 
  return response;
};

Abdominous

Answer 1

I have used the promise concept and it does returning the response properly for me. Sample JSON {"user_id": "1001"}

var Redshift = require('node-redshift');
   
const config = {
  user: 'user',
  database: 'database',
  password: 'password',
  port: port,
  host: 'hostname',
};

// The values passed in to the options object will be the difference between a connection pool and raw connection
var redshiftClient = new Redshift(config, {rawConnection:true});


exports.handler =  async (event) => {
return new Promise(function(resolve, reject){

redshiftClient.connect(function(err){
    if(err) throw err;
    else{
      redshiftClient.parameterizedQuery('SELECT * FROM customer where user_id = $1', [event.user_id], {raw: true}, function(err, data){
        if(err) throw reject(err);
        else{
          resolve(data);
          redshiftClient.close();
        }
      });
    }
  }); 
});

};

Abdominous