Aws lambda async and sync issue - node.js

Question

I have a requirement where i need to query on a table then loop through the result and query another table inside a loop .. But i tried using synchronize node js module . But sometime api ends with timeout error with this method. Now i am trying my code in below way but no luck.
var notification = {
TableName: "Tablename",
KeyConditionExpression:"#userId =:userid and #datetime <=:datetime",
ScanIndexForward: false,
ExpressionAttributeNames: {
"#userId": "userId",
"#datetime":"datetime"
},
ExpressionAttributeValues: {
":userid" :userId,
":datetime" :datetime
}
};
docClient.query(notification, function(err, result) {
if (err) {
context.succeed({success: false, message : JSON.stringify(err, null, 2),method:"notification",type:type});
}else{
result = result.Items;
if (result.length>0) {
for(var i=0;i<result.length;i++){
result[k]['CafeDetail']=getDetail(result[k].CafeID,function (data) {
});
if (k ==(result.length -1)) {
context.succeed({success: true,data:result, message : "Notification list",method:"notification",type:type});
}
}
}
}
});
function getDetail(CafeID,callback) {
var param = {
TableName: "Tablename",
ProjectionExpression:"CafeName,Cafe_MainImage",
KeyConditionExpression:"CafeID =:cafeID",
ExpressionAttributeValues: {
":cafeID" :CafeID
}
};
docClient.query(param, function(err, CafeDetail) {
if (err) {
console.log (err)
callback(err);
} else {
callback(CafeDetail.Items);
console.log(CafeDetail.Items);
}
});
}
On output this variable (result[k]['CafeDetail']) is always coming as undefined . However console.log inside getDetail function print the result.
I am newbie to aws lambda with node js .. Any help will be appreciated .
Thanks in Advance

Answer 1

I just got solution to my question . So i am posting it,may be it will help someone else facing same issue
var notification = {
TableName: "Tablename",
KeyConditionExpression:"#userId =:userid",
Limit: 12,
ScanIndexForward: false,
ExpressionAttributeNames: {
"#userId": "userId",
},
ExpressionAttributeValues: {
":userid" :userId
}
};
docClient.query(notification, function(err, result) {
if (err) {
context.succeed({success: false, message : JSON.stringify(err, null, 2),method:"notification",type:type});
}else{
var ret =[];
var results =result.Items;
if (results.length>0) {
results.forEach(function(result, i) {
console.log(i);
var param = {
TableName: "Tablename",
ProjectionExpression:"CafeName,Cafe_MainImage",
KeyConditionExpression:"CafeID =:cafeID",
ExpressionAttributeValues: {
":cafeID" :result.CafeID
}
};
docClient.query(param, function(err, CafeDetail) {
if (err) {
context.succeed({success: false, message : JSON.stringify(err, null, 2),method:"notification",type:type});
} else {
console.log(CafeDetail.Items);
CafeDetail =CafeDetail.Items;
result['CafeDetail']=CafeDetail
console.log(result);
if (i === results.length -1) { // last iteration
context.succeed({success: true,data:results, message : "Notification list",method:"notification",type:type});
}
}
});
});
}else{
context.succeed({success: true,data:result, message : "Notification list",method:"notification",type:type});
}
}
});