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value not setting in the variable which is defined outside in NodeJS

I'm new to NodeJS so please apologize if below code is not up-to the standard. I would like to access isSuccess value outside of this function stepfunctions.listExecutions
I tried below code but I'm getting the value is undefined not getting the expected output. I did some internet search and came to know in NodeJS we can't set the value which is defined in globally but I've use case and I'm pretty sure this is a common case for others too - where I would like to access this isSuccess value after my execution.
const AWS = require('aws-sdk');
const stepfunctions = new AWS.StepFunctions({
region: process.env.AWS_REGION
});
var params = {
stateMachineArn: 'arn:aws:states:us-west-1:121:stateMachine:test',
maxResults: '2',
nextToken: null,
statusFilter: 'SUCCEEDED'
};
var isSuccess
stepfunctions.listExecutions(params, function (err, data) {
if (err) console.log(err, err.stack);
else
data.executions.forEach(function (result) {
let params = {
executionArn: result.executionArn
};
stepfunctions.describeExecution(params, function (err, data) {
if (err) console.log(err, err.stack);
else {
isSuccess = 'true'
}
});
});
console.log('isSuccess: ' +isSuccess)
});
Expected output:
isSuccess: true
But I'm getting
isSuccess: undefined
Could you please help me to resolve this issue. Appreciated your help and support on this.

This is how you can wrap it on promise
let isSuccess;
const listExecute = function(params) {
return new Promise((resolve, reject) => {
stepfunctions.listExecutions(params, function (err, data) {
if (err) reject(err);
else
data.executions.forEach(function (result) {
let params = {
executionArn: result.executionArn
};
stepfunctions.describeExecution(params, function (err, data) {
if (err) reject(err);
else {
resolve(true)
}
});
});
});
})
}
async function getOutout(params) {
try {
isSuccess = await listExecute(params);
console.log(isSuccess, 'Output')
} catch(e) {
console.log(e)
}
}
getOutout(params)
Also you can export the listExecute so that you can use this function outside of this file.
module.exports = {listExecute}

array push results in empty array javascript

I am trying to store API results into an array.
The data is displayed in console, but on pushing the data into an array, the array is still empty.
Here's the code:
app.post('/fetchFavoriteTweets/', verifyToken, function(req, res) {
var favorites = [];
dbConn.then( function (database) {
var dbo = database.db("twitter_search");
dbo.collection('users').findOne(
{ _id: ObjectId(req.userId) }, function(err, result) {
if(err) throw err;
if(!result.hasOwnProperty('favorite_tweets')) {
res.status(404).json({msg:'record not found'});
}
else {
result.favorite_tweets.forEach(function (tweet) {
T.get('statuses/show', {id: tweet.id}, function(err, data, response) {
if(!err){
favorites.push(data);
console.log(data); //this returns data
} else {
console.log(err);
}
});
});
console.log(favorites);
// res.status(200).json({msg:'success', data:favorites});
}
});
}).catch(function(e){console.log(e)})
});

It looks like you're defining the favorites array within the scope of the function callback. Try putting var favorites = []; above you app.post() call instead.
Also, keep in mind that it will only have a value after the callback is complete, so any synchronous code later down the line will only see the empty array value.

I've updated your code to get favorites by storing separately the promise and call it afterwards:
UPDATE
As you can see in the demo, i have 2x console.log at the bottom, the first one(C1) is contained in the promise favoritesPromise () and the second (C2) is after the promise.
Synchronous actions will never wait for asynchronus actions to take place, therefore in my example C2 will always be outputted before C1, even if console.log(1 ... ) is before console.log(2 ... ), they'll appear reversed in the console.
In the promise i added a setTimeout of 1ms to mock a request, it was all it took to achieve the current output. Another thing you can test is removing the setTimeout then output will change a bit, your promise becomes synchronus until it reaches resolve(favorites), that means favorites has all the data by now, but when resolve takes place, it becomes async, and in your console you will still see C2 first (but now with data) and C1 second.
In my earlier answer i tried to implement this reasoning to your code.
Keep it async folks!
var favorites = [];
var favoritesPromise = () => {
return new Promise((resolve, reject) => {
console.log('Retrieving data from the internet.');
// This timeout mocks your request to anything that is async or promie
setTimeout(() => {
console.log('Request done')
let resultFavorite_tweets = [{
id: 1,
name: 'a dog'
}, {
id: 2,
name: 'a cat'
}];
resultFavorite_tweets.forEach(item => {
favorites.push(item.name);
})
resolve(favorites);
// if you have an error use
// reject(err)
}, 1);
});
}
favoritesPromise().then(favList => {
console.log(1, 'this will always contain data from the internet, but will always be last', favList);
})
console.log(2, 'this will be empty (unless you remove setTimeout), but will always be first', favorites);
app.post('/fetchFavoriteTweets/', verifyToken, function(req, res) {
const favoritesPromise = () => {
return new Promise((resolve, reject) => {
var favorites = [];
dbConn.then(function(database) {
var dbo = database.db("twitter_search");
dbo.collection('users').findOne({
_id: ObjectId(req.userId)
}, function(err, result) {
if (err) reject(err);
if (!result.hasOwnProperty('favorite_tweets')) {
res.status(404).json({
msg: 'record not found'
});
} else {
result.favorite_tweets.forEach(function(tweet) {
T.get('statuses/show', {
id: tweet.id
}, function(err, data, response) {
if (!err) {
favorites.push(data);
console.log(data); //this returns data
} else {
console.log(err);
reject(err);
}
});
resolve(data);
});
console.log(favorites);
// res.status(200).json({msg:'success', data:favorites});
}
});
}).catch(function(e) {
reject(e)
})
});
}
// Here you call the promise to retrieve "favorites"
favoritesPromise().then(favoritesList => {
console.log('your favorites array', favoritesList)
})
})

Try next code
app.post('/fetchFavoriteTweets/', verifyToken, function (req, res) {
var favorites = [];
dbConn.then(function (database) {
var dbo = database.db("twitter_search");
dbo.collection('users').findOne(
{ _id: ObjectId(req.userId) }, function (err, result) {
if (err) throw err;
if (!result.hasOwnProperty('favorite_tweets')) {
res.status(404).json({ msg: 'record not found' });
}
else {
// Counter
let count = result.favorite_tweets.length;
result.favorite_tweets.forEach(function (tweet) {
T.get('statuses/show', { id: tweet.id }, function (err, data, response) {
// Decrease count
count -= 1;
if (!err) {
favorites.push(data);
// Check if count is zero
if (count === 0) {
console.log(favorites);
res.status(200).json({msg:'success', data:favorites});
}
} else {
console.log(err);
}
});
});
}
});
}).catch(function (e) { console.log(e) })
});

Callback NodeJS & insert data with mongoose

I know this topic as already asked many times before but I didn't find the right answer to do what I want.
Actually, I try to save two different list of JSON object in MongoDB via Mongoose. To perform both at the same time I use 'async'.
However, when I save it with the command insertMany() I get an error because he calls the callback of async before finishing the insertMany(). Therefore answer[0] is not defined.
What will be the proper way of doing it ?
Here is my code with the async:
const mongoose = require("mongoose");
const async = require("async");
const utils = require("../utils");
const experimentCreate = function(req, res) {
let resData = {};
let experimentList = req.body.experiment;
let datasetList = req.body.datasetList;
async.parallel(
{
dataset: function(callback) {
setTimeout(function() {
answer = utils.createDataset(datasetList);
callback(answer[0], answer[1]);
}, 100);
},
experiment: function(callback) {
setTimeout(function() {
answer = utils.createExp(experimentList);
callback(answer[0], answer[1]);
}, 100);
}
},
function(err, result) {
if (err) {
console.log("Error dataset or metadata creation: " + err);
sendJSONresponse(res, 404, err);
} else {
console.log("Experiment created.");
resData.push(result.dataset);
resData.push(result.experiment);
console.log(resData);
sendJSONresponse(res, 200, resData);
}
}
);
};
Then the two functions called createExp and createDataset are the same in another file. Like this:
const createDataset = function(list) {
let datasetList = [];
for (item of list) {
let temp = {
_id: mongoose.Types.ObjectId(),
name: item.name,
description: item.description,
type: item.type,
};
datasetList.push(temp);
}
Dataset.insertMany(datasetList, (err, ds) => {
if (err) {
console.log("Error dataset creation: " + err);
return [err, null];
} else {
console.log("All dataset created.");
return [null, ds];
}
});
};

There's a few problems with your code. For one, you're not returning anything in your createDataset function. You're returning a value in the callback of insertMany but it doesn't return that value to the caller of createDataset as it's within another scope. To solve this issue, you can wrap your Dataset.insertMany in a promise, and resolve or reject depending on the result of Data.insertMany like this:
const createDataset = function(list) {
let datasetList = [];
for (item of list) {
let temp = {
_id: mongoose.Types.ObjectId(),
name: item.name,
description: item.description,
type: item.type,
};
datasetList.push(temp);
}
return new Promise((resolve, reject) => {
Dataset.insertMany(datasetList, (err, ds) => {
if (err) {
console.log("Error dataset creation: " + err);
reject(err);
} else {
console.log("All dataset created.");
resolve(ds);
}
});
});
};
Now your return object is no longer going to be an array so you won't be able to access both the error and the result via answer[0] and answer[1]. You're going to need to chain a then call after you call createDataset and use callback(null, answer) in the then call (as that means createDataset executed successfully) or use callback(err) if createDataset throws an error like below:
dataset: function(callback) {
setTimeout(function() {
utils.createDataset(datasetList).then(answer => {
callback(null, answer);
}).catch(err => callback(err)); // handle error here);
}, 100);
}
Note: You'll most likely need to alter your createExp code to be structurally similar to what I've produced above if it's also utilizing asynchronous functions.

Use ldapjs with promise

I want to convert the following code to use promise. It is working and output a user's attributes within the active directory.
var client = ldap.createClient({
url: ldap_url
});
client.bind(ldap_username, ldap_password, function (err) {
client.search(ldap_dn_search, opts, function (err, search) {
search.on('searchEntry', function (entry) {
var user = entry.object;
// It is working!!!. It outputs all user attributes.
console.log(user);
});
});
});
The following is my attempt, butit doesn't output anything.
var Promise = require('promise');
var client_bind = Promise.denodeify(client.bind);
var client_search = Promise.denodeify(client.search);
client_bind(ldap_username, ldap_password)
.then(function(err){
client_search(ldap_dn_search, opts)
.then(function(search){
var search_on = Promise.denodeify(search.on);
search_on('searchEntry')
.then(function(entry){
var user = entry.object;
// It doesn't output anything !!!
console.log(user);
});
});
});

I had the same problem.
Search emits events, so we need something that processes them and passes further along the chain.
Here is piece of code, that works for me:
var ldap = require('ldapjs');
var promise = require('bluebird');
var client = ldap.createClient({url: app.settings['ldap']['server']});
var uid;
promise.promisifyAll(client);
function searchPromise(res, notfoundtext) {
return new Promise(function(resolve, reject) {
var found = false;
res.on('searchEntry', function(entry) {
found = true;
resolve(entry);
});
res.on('error', function(e) {
reject(e.message);
});
res.on('end', function() {
if (!found) {
reject(notfoundtext);
}
});
});
}
client.searchAsync(app.settings['ldap']['baseDn'], {filter: '(mail='+credentials.email+')', scope: 'sub'})
.then(function(res) {
return searchPromise(res, 'User isn\'t exists.');
})
.then(function (entry) {
uid = entry.object.uid;
return client.bindAsync(entry.object.dn, credentials.password);
})
.then(function() {
return client.searchAsync('cn='+app.settings['ldap']['group']+',cn=groups,'+app.settings['ldap']['baseDn'], {scope: 'sub', filter: '(memberUid='+uid+')'});
})
.then(function(res) {
return searchPromise(res, 'User is not in group ' + app.settings['ldap']['group']);
})
.then(function() {
console.log('All is ok');
})
.catch(function(message) {
console.log('Error:' + message);
});
Immediately after the search I add one more step that catches the events, processes them, and passes it further along the chain. This makes the function searchPromise.
Good luck coding )

Most likely those methods do require to be called on client as a context, so you will need to bind() them before passing them to Promise.denodeify:
var client_bind = Promise.denodeify(client.bind.bind(client));
var client_search = Promise.denodeify(client.search.bind(client));
Also, a proper use of promises would look like this:
client_bind(ldap_username, ldap_password).then(function() {
return client_search(ldap_dn_search, opts);
// ^^^^^^ always return something from the callback
}).then(function(search) { // flatten your chain
return Promise.denodeify(search.on).call(search, 'searchEntry');
// ^^^^^^ an alternative to `bind`
}).then(function(entry){
var user = entry.object;
console.log(user);
}).catch(function(err) { // always catch errors!
console.error(err);
});

Using Bluebird Promises, the easy way to do this is to create your client normally, and then run the promisifyAll() on the client.
var ldap = require('ldapjs');
var Promise = require('bluebird');
var client = ldap.createClient({
url: 'ldap://my-server:1234',
});
Promise.promisifyAll(client);
Now you can call client.addAsync() and client.searchAsync() and such.
client.bindAsync(secUserDn, secUserPassword)
.then(doSearch) // if it works, call doSearch
.catch(function (err) { // if bind fails, handle it
console.error('Error on bind', err)
});
function doSearch(data) {
client.searchAsync('CN=A Test,OU=Users,DC=website,DC=com', options)
.then(function (data) { // Handle the search result processing
console.log('I got a result');
})
.catch(function (err) { // Catch potential errors and handle them
console.error('Error on search', err);
});
}

i had the same issue here but i solved it by adding promise and resolve the response without using bluebird, this is an exemple of my code :
async getLdapUser(username: any): Promise<any> {
let myPromise = new Promise<boolean>((resolve, reject) => {
console.log('ssssssssss', username);
const adSuffix = 'OU=xxxx,OU=xxxxx,DC=xxxxxxx,DC=xxxxxx';
const password = 'xxxxxxxxxxxxx';
// Create client and bind to AD
const client = ldap.createClient({
url: 'ldap://1.1.1.1:389',
});
// promise.promisifyAll(client);
let resp = false;
// console.log(client);
client.bind('userTest', password,(err: any) => {
console.log('RESP', resp);
if (err) {
console.log('Error in new connetion ' + err);
} else {
/*if connection is success then go for any operation*/
console.log('Success');
const searchOptions: {} = {
scope: 'sub',
filter: '(sAMAccountName=' + username + ')',
attributes: ['sAMAccountName'],
};
client.search(adSuffix, searchOptions, (err: any, res: any) => {
assert.ifError(err);
res.on('searchEntry', (entry: any) => {
resp = true;
});
res.on('error', (error: any) => {
console.log('err');
reject(error.message);
});
await res.on('end', (result: any) => {
resolve(resp);
});
});
}
});
});
return myPromise;
}

Getting data from rethinkdb database, manipulating said data, then updating the database with the manipulated docs

I am looking to do a get, run a function on the results which will do some manipulation by updating a field, and then put that doc back into the database. Really my issue is being able to chain together multiple DB calls. I have been struggling with this the past week or so. Any suggestions appreciated, thanks.
Here is what I have tried so far but I am receiving an error:
function geocode_cleanup(request, response, next) {
r.table('dealer_locations').filter(r.row('geodata').match('No geodata found.'))
.do(function(row) {
var geodata = opencage_geocoder.geocode(row.Address, function(error, response) {
if (error) {
console.log("Error.");
row.geodata = "No geodata found.";
row.active = true;
} else if (response.length == 0) {
console.log("Empty response.");
} else {
console.log("Success.");
console.log(response);
var latitude = response[0].latitude;
var longitude = response[0].longitude;
row.geodata = r.point(longitude, latitude);
row.active = true;
}
});
return r.table('dealer_locations').update({
geodata: geodata
})
}).run(conn, function(error, cursor) {
response.setHeader("Content-Type", "application/json");
if (error) {
handleError(response, error);
} else {
cursor.toArray(function(error, results) {
if (error) {
handleError(response, error);
} else {
response.send(results);
};
});
}
next();
})
};
Also, this gives the desired results returned in the response, but the second db action never happens because I am still inside of the same db connection I think:
function geocode_cleanup(request, response, next) {
var conn = request._rdbConn;
r.table('dealer_locations').filter({geodata: "No geodata found."}).run(conn, function(error, cursor) {
if (error) {
handleError(response, error);
} else {
cursor.toArray(function(error, results) {
if (error) {
handleError(response, error);
} else {
var i = 1;
async.forEach(results, function(item, callback) {
var address = (item.Address + " " + item.City).toString();
opencage_geocoder.geocode(address, function(err, res) {
if (err) {
console.log(i);
console.log("Error.");
item.id = i;
item.geodata = "No geodata found.";
item.active = true;
i++;
callback();
} else if (res.length == 0) {
console.log(i);
console.log("Empty response.");
i++;
callback();
} else {
console.log(i);
console.log("Success.");
console.log(res);
var latitude = res[0].latitude;
console.log(i + " " + latitude);
var longitude = res[0].longitude;
console.log(i + " " + longitude);
item.id = i;
item.geodata = r.point(longitude, latitude);
item.active = true;
i++;
callback();
}
});
}, function() {
r.table('dealer_locations').insert(results, {
conflict: "replace"
}).run(request._rdbConn, function(error, results) {
if (error) {
console.log("Data not inserted!");
} else {
console.log("Data inserted!");
}
});
console.log("Done!");
response.send(results);
});
}
})
}
})
}

Here's a possible solution which uses promises to organize the code a little bit.
// Guarantee support for promises and provide the `promisify` function
var Promise = require('bluebird');
// Promisify the geocode function to make it easier to use
var geocode = Promise.promisify(opencage_geocoder.geocode);
function geocode_cleanup(request, response, next) {
var conn = request._rdbConn;
r
.table('dealer_locations')
.filter(r.row('geodata').match('No geodata found.'))
.coerceTo('array')
.run(conn)
.then(function(rows) {
// This promise will be resolve when all rows have been geocoded and updated
// We map the rows into an array of promises, which is what Promise.all takes
return Promise.all(rows.map(function (row) {
return geocode(row.Address)
.then(function (response) {
console.log("Success.");
var latitude = response[0].latitude;
var longitude = response[0].longitude;
row.geodata = r.point(longitude, latitude);
row.active = true;
// Return the row
return row;
});
});
}));
})
.then(function (rows) {
// Now that all `dealer_locations` have been updated, re-query them
return r
.table('dealer_locations')
.insert(rows, {conflict: "update", return_changes: true})
.run(conn);
})
.then(function (results) {
// Send the response;
response.setHeader("Content-Type", "application/json");
response.send(results);
return;
})
.catch(function (err) {
return handleError(null, error);
})
};
Some problems I noticed with your code:
1. Use of do
r.table('dealer_locations').filter(r.row('geodata').match('No geodata found.'))
.do(function(row) {
var geodata = opencage_geocoder.geocode ...
})
In this code snippet, you use a JS function inside of do. You can't do that. Remember that what happens inside of do happens in the RethinkDB server (not in your Node.js server). Your RethinkDB server has no knowledge of your opencage_geocoder function and so this woudn't work.
Whatever do returns must be a valid ReQL query or ReQL expression. You can't execute arbitrary JavaScript inside of it.
If you want to run JavaScript with your query results, you have to .run the query and then do whatever you want to do inside the callback or .then function. At that point, that code will get executed in JavaScript and not in your RethinkDB server.
2. Use of update
return r.table('dealer_locations').update({
geodata: geodata
})
The update method can only update a single document. You can't pass it an array of documents. In this scenario you what have needed to do r.table().get().update() in order for this to work, because you have to be referencing a single document when you update something.
If you have an array of documents that you want to update, you can use the forEach method.
r.table('hello')
.merge({
'new_property': 'hello!'
})
.forEach(function (row) {
// Insert that property into the document
return r.table('hello').get(row.id).update(row);
})
You can also do this (which you are already doing):
r.table('hello')
.merge({
'new_property': 'hello!'
})
.do(function (rows) {
// Insert that property into the document
return r.table('hello')
.insert(rows, {conflict: "update", return_changes: true});
})

OK, I have a suggestion. This queries for the documents you're interested in, modifies them (on your app server, not in the db) and then reinserts them using the nifty conflict: 'update' option. It also uses promises because I think that's a bit cleaner.
function geocode_cleanup(request, response, next) {
r.table('dealer_locations')
.filter(r.row('geodata').match('No geodata found.'))
.run(conn).then(function(cursor) {
var to_update = [];
return cursor.toArray().then(function getGeocodes(rows) {
return rows.map(function getGeocode(row) {
row.geodata = opencage_geocoder.geocode(row.Address, function(error, response) {
if (error) {
console.log("Error.");
row.geodata = "No geodata found.";
row.active = true;
} else if (response.length == 0) {
console.log("Empty response.");
} else {
console.log("Success.");
console.log(response);
var latitude = response[0].latitude;
var longitude = response[0].longitude;
row.geodata = r.point(longitude, latitude);
row.active = true;
}
});
return row;
});
});
}).then(function doneGeocoding(modified_rows){
return r.table('dealer_locations')
.insert(modified_rows, {conflict: "update", return_changes: true})('changes')
.coerceTo('array')
.run(conn);
}).then(function finishResponse(changes){
response.setHeader("Content-Type", "application/json");
response.send(results);
next();
}).catch(function(err) {
// handle errors here
});
};
Caveat emptor, I haven't run this, so there may be syntax errors and things