CODEWITHSUNDEEP
node.jsexpresscallback
Kaya Toast
Kaya Toast

Reputation: 5513

separating functions/files in node and callbacks

I am trying to organise my code in 3 files

so that for a GET request, I can respond with the resulting rows. I am simply unable to wrap my head around the callback functions. How can I return the resulting rows to the client ?

File: db_queries.js

function getUserData (userId, fn){
    client.query("select * from participationTable where ? in (userId1, userId2)", userId, function(err,rows){
        if (err) {
            return fn(new Error('(customError) unable to find ongoing games'));
        } else {
            return fn(null, rows);
        }
    });
}
module.exports.getUserData = getUserData;

File: general_functions.js

var db = require('./db_queries');
function getUserParticipationDeatils(req, function(err, rows){
    db.getUserData(req.user.userId, function(err, rows){
            if (err){ return done(err); }
            // 'rows' is accessible here
            // but how can I send it ?
        });
});
module.exports.getUserParticipationDeatils = getUserParticipationDeatils;

File: basic_routes.js

var general_functions = require('./general_functions');
app.get('/getUserParticipation', function (req, res) {  
    general_functions.getUserParticipationDeatils(req, function(err, rows){
        if (err){ return done(err); }
        return res.send(JSON.stringify(rows));
    }); 
});

Please help me structure the functions in the file general_functions.js

Upvotes: 0

Views: 300

Answers (1)

Chirag Jain
Chirag Jain

Reputation: 2418

Change your getUserParticipationDeatils to accept a callback fn just like your getUserData function.

Something like this:

var db = require('./db_queries');
function getUserParticipationDeatils(req, fn){
    db.getUserData(req.user.userId, function(err, rows){
        if (err){ return fn(err); }
        fn(null, rows);
    });
});
module.exports.getUserParticipationDeatils = getUserParticipationDeatils;

Upvotes: 1

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