associative array show empty value - node.js

Question

hi everyone I tried to develop chat app using node js and socket.io for back end , my problem is empty value of associated array
socket.on('nickName', (data) => {
console.log(data)
var roomId;
con.query("SELECT user_id FROM nickname WHERE user_id = '" + String(data) + "'", (err, result) => {
if (err) {
throw err;
}
console.log(result)
if (result == undefined || result[0] == undefined) {
con.query("INSERT INTO nickname (user_id,socket_id) VALUES ('" + data + "','" + socket.id + "')")
} else {
con.query("UPDATE nickname SET socket_id = '" + socket.id + "' WHERE user_id = '" + data + "' ", (err, result) => {
})
}
})
con.query("SELECT * FROM room WHERE user_id = '" + data + "'", (err, result) => {
if(err){
throw err;
}else{
io.to(socket.id).emit('getChatList', { "chatList": result })
var unread = {}
result.forEach(Element=>{
roomId = Element.room_name
con.query("SELECT COUNT(*) FROM message WHERE room_id = '"+roomId+"' AND seen=0 AND to_user='"+data+"'",(err,unseen)=>{
if(err){
throw err;
}else{
// I trying set value to unread array
unread[roomId] =unseen[0]['COUNT(*)'] ;
// unread array work correctly
console.log(unread)
}
})
// problem is here print unread empty ({})in
// console.
console.log(unread)
})
}
})
});
unread array show empty value but when I put for example unread['A'] ='C' ; out of query block everything works fine , anyone can help me?

Answer 1

I solved my problem by using async.each() instead of result.forEach()
socket.on('nickName', (data) => {
console.log(data)
var roomId;
clients[data] = socket.id;
con.query("SELECT user_id FROM nickname WHERE user_id = '" + String(data) + "'", (err, result) => {
if (err) {
throw err;
}
console.log(result)
if (result == undefined || result[0] == undefined) {
con.query("INSERT INTO nickname (user_id,socket_id) VALUES ('" + data + "','" + socket.id + "')")
} else {
con.query("UPDATE nickname SET socket_id = '" + socket.id + "' WHERE user_id = '" + data + "' ", (err, result) => {
})
}
})
con.query("SELECT * FROM room WHERE user_id = '" + data + "'", (err, result) => {
if(err){
throw err;
}else{
io.to(socket.id).emit('getChatList', { "chatList": result })
var unread = {};
asyncc.each(result,function(Element,callbackk){
roomId = Element.room_name
console.log(Element)
con.query("SELECT COUNT(*) FROM message WHERE room_id = '"+Element.room_name+"' AND seen=0 AND to_user='"+data+"'",(err,unseen)=>{
if(err){
throw err;
}else{
console.log(unseen)
console.log(Element.room_name)
unread[Element.room_name] = unseen[0]['COUNT(*)'] ;
}
callbackk();
})
},function(er){
console.log(unread)
})
}
})
});