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Express resolving route before API call completes

Ok, full disclosure I am a hobby coder so I understand there to be gaps in my knowledge. However I've tried all sorts of solutions for this and have been unable to get a working answer.
DESIRED RESULT
I make a call to my Express server, it fetches data from an external API and renders once the data has been retrieved.
PROBLEM
I cannot seem to make Express wait no matter how I lay out the async/await pattern. Currently my code is as follows:
Express.js
app.get('/getInventory', async (req, res) => {
try {
let inventory = await api.getInventory(req.query.id)
console.log(inventory)
res.json(inventory)
}
catch(err) {
console.log(err)
}
})
My api.js is currently as such:
exports.getInventory = async function(id){
let data = await manager.getInventoryContents(id, 570, 2, true, (err, inventory) => {
if (err) {
console.log(err)
Promise.reject(err)
}
else {
console.log('Success')
Promise.resolve(inventory)
}
})
return data
}
In case you're wondering I have the console.log() actions just to try and see when something is happening.
WHAT I AM GETTING SO FAR
With just about every variation I am getting the Express.js inventory as undefined (similarly no data being sent to the client), however I AM receiving a Success message (or even the inventory itself) from api.js.
I am guessing the right syntax is obvious once I complete it but I cannot seem to get it to function properly. What am I missing?

Try this:
exports.getInventory = async function(id){
return new Promise((resolve, reject) => {
manager.getInventoryContents(id, 570, 2, true, (err, inventory) => {
if (err) {
console.log(err);
reject(err);
}
else {
console.log('Success');
resolve(inventory);
}
}
}
}

Database Querying function not running asynchronously

So I created a function in my node server which takes in a query string, runs it on my db, and returns the results. I then wanted to use my function asynchronously using async await throughout my routes instead of having nested query within, nested query, within nested query etc.
So here is the code:
const runQuery = queryString => {
console.log("...runQuery")
db.query(queryString, (error, results, fields) => {
if (error) {
console.log("runQuery: FAILURE");
return error;
}
else {
console.log("runQuery: SUCCESS");
return(results);
}
})
}
register.post("/", async (req, res) => {
console.log(req.body);
const results = await runQuery("select * from test1");
res.send(results);
})
The database should have 3 entries, but unfortunately, it returns nothing. Meaning results is an empty variable when it is sent, meaning JS never properly waits for it to capture the db results. How can I use my function asynchronously, and how is this even feasible?

It seems your function "runQuery" does not return a promise, in fact, it's not returning anything. You are using "return" in the callback of the db.query function, not the function "runQuery" itself.
Since runQuery is performing an asynchronous operation, the result ought to be resolved via a promise (which is what the "await" in your request handler is looking for).
I'm not exactly sure but it seems you are using MySql, and I could not find anything on the npm page of the mysql package regarding the query being promisified, so we'll promisify it ourselves:
const runQuery = (queryString) => new Promise((resolve,reject) => {
console.log("...runQuery")
db.query(queryString, (error, results, fields) => {
if (error) {
console.error("runQuery: FAILURE");
reject(error);
} else {
console.log("runQuery: SUCCESS");
resolve(results);
}
})
})
register.post("/", async (req, res) => {
console.log(req.body);
try{
const results = await runQuery("select * from test1");
res.send(results);
}catch(e){
console.error(`ERROR THROWN BY runQuery:`,e);
res.status(500).send({
message: e.message || "INTERNAL SERVER ERROR"
})
}
})
Note that if an error occurs, our promisified function will reject the error and it will NOT be stored in the "results" variable in our request handler. Instead, an error will be thrown which needs to be handled. Therefore, it is always a good practice to put any async/await calls inside a try/catch.

How to correctly string together Promises for synchronous code execution

I posted a similar question several days ago but I have made some changes and commenting on that question was becoming tedious, so it was recommended I ask a new question.
The idea is that I want to execute four equations synchronously. Inside those equations are HTTP requests. I have two of the equations working properly and but there is one equation that involves two POST requests and a GET requests. The second requests relies on the first and the third request relies on the second.
I have tried several different methods to get this to work. I have tried flattening my promises, returning the promises. All kinds of things, with no luck. I am not sure where I am going wrong.
Synchronous code snippet:
this.getData1(user, userID).then(() =>
{
this.getData2(user, userID)
.then(() =>
{
this.getData3(user, lan).then(() =>
{
this.userCheck(user);
})
});
});
I have getData2 and getData3 working.
getData1 looks like:
getData1(user: string, id: string){
console.log('grabbing CC information', id, user);
return new Promise((resolve, reject) =>
{
var status: string;
this._apiService.getAssertion(id).subscribe((data: any) =>
{
let assert = data.toString();
this._apiService.getToken(assert).subscribe((data: any) =>
{
let tkn = data.access_token.toString();
this._apiService.ccMeta(tkn, guid).subscribe((data: any) =>
{
parseString(data, (err, result) =>
{
if (err)
{
throw new Error(err);
}
else
{
status = result['entry']['content'][0]['m:properties'][0]['d:status'][0];
this.ccData.push(
{
key: 'userStatus',
value: status
})
}
});
});
});
});
resolve()
});
}
I also tried something like this previously. It did not work either.
apiService.getAssertion(id).then(assert =>
{
return apiService.getToken(assert.toString(), user);
}).then(data =>
{
return apiService.ccMeta(data.access_token.toString(), id);
}).then(parseStringPromise).then(information =>
{
this.ccData.push(
{
key: 'userStatus',
value: information.entry
});
});
Inside this function the getAssertion function is a POST request. The getToken function is another POST request that relies on the assertion from the first POST request. Finally, ccMeta is a get request that relies on the token from the second POST request.
I would expect getData1 to execute first, then getData2, then getData3, and finally, userCheck. Inside getData1 I need the assertion, then the token, and then get request to execute synchronously. The code snippet above is not executing correctly. The assertion is not properly being used in the getToken equation.
I would greatly appreciate some help.

Since these HTTP calls are in fact observables and not promises, I think you should look into observable composition using pipe and switchMap for instance. If you still want you method to return a promise, it could look like this:
getData1(user: string, id: string) {
console.log('grabbing CC information', id, user);
return new Promise((resolve, reject) => {
this._apiService.getAssertion(id)
.pipe(
switchMap((data: any) => {
let assert = data.toString();
return this._apiService.getToken(assert);
}),
switchMap((data: any) => {
let tkn = data.access_token.toString();
return this._apiService.ccMeta(tkn, guid);
}),
)
.subscribe(
data => {
parseString(data, (err, result) => {
if (err) {
reject(new Error(err));
return;
}
const status: string = result['entry']['content'][0]['m:properties'][0]['d:status'][0];
this.ccData.push({
key: 'userStatus',
value: status
});
resolve();
});
},
);
});
}

Sails Waterline ORM query inside array.map()

Code snippet below is using sails waterline ORM to make DB queries and sending response. However, the execution flow is weird, The code outside of map function is running before the map function has finished executing. 'I am outside of map' is being printed in the console before 'I am inside of map'. I think it can be solved this using Promise or async / await. I have tried using Promise.all() below, but it doesn't work, the response is always an empty array. I would be grateful if you could give an example on how to solve this kind of issues.
allMembers: (req, res) => {
const projectId = req.params.id;
ProjectMembers.find({projectId: projectId}).exec( (err, members) => {
if(err) res.serverError("bad request!");
if(members.length === 0) res.notFound({message: "No members are found for this project!"});
let membersInfo = [];
let promise = Promise.all(members.map(m => {
User.findOne({id: m.userId}).exec( (err, user) => {
if(err) membersInfo.push({name: null, userId: null, email:null,rate:null, error: 'Internal error!'})
else if(!user) membersInfo.push({name: null, userId: null, email:null,rate:null, error: 'No user found'})
else membersInfo.push({name: user.name, userId: user.id, rate: m.rate, error: null})
console.log("i am inside of map");
})
}));
console.log("I am outsie of map")
promise.then( (resolve) => {return res.ok({members: membersInfo})});
}

I was about to tell you "don't use queries in .map", but on looking, I think your code is quite close to working. The argument of Promise.all has to be an array of promises. Each User.findOne is indeed a promise - the stumbling block is that once you use .exec it no longer returns a promise.
I think the answer is to do your processing inside the .then instead of right inside the .map:
ProjectMembers.find({projectId: projectId}).exec( (err, members) => {
if(err) return res.serverError("bad request!");
if(members.length === 0) return res.notFound({message: "No members are found for this project!"});
let promise = Promise.all(members.map(m => User.findOne({id: m.userId})));
promise.then( (values) => {
// values is the array of user objects returned from the array of queries
let membersInfo = values.map((user) => {
if (!user) {
return {name: null, userId: null, email:null,rate:null, error: 'No user found'};
} else {
return {name: user.name, userId: user.id, rate: m.rate, error: null};
}
});
return res.ok({members: membersInfo});
}, (err) => {
return res.serverError("Error finding users");
});
The promise only has a single fail callback, so you lose the ability to individually catch and handle querying errors (though you can still individually handle not-found results).

Error : Callback was already called when using pg-promise with async series

I'm having trouble understanding the output printed why executing this code :
1
2
Unhandled rejection Error: Callback was already called.
It seems like both then and catch are executed when the query is successful.
Any idea ?
Cheers
async.series([
function(callback) {
db.none(query)
.then(function () {
return callback(null, true);
})
.catch(function (err) {
return callback(err, null);
});
},
function(callback) {
db.any(query)
.then(function (data) {
console.log('1')
return callback(null, data);
})
.catch(function (err) {
console.log('2')
console.log(err);
return callback(err, null);
});
}
],
function(err, results) {
if (results && !results[1].isEmpty()) {
// do something
}
});
EDIT :
TypeError: results[1].isEmpty is not a function
It seems like the problem come from the rest of the code and was just a simple undefined function error, thanks.
But i still don't understand something : why is this error catched inside the second query instead of outside the async queries ?

I'm the author of pg-promise.
You should never use async library with pg-promise, it goes against the concept of shared/reusable connections.
Implementation with proper use of the same connection, via a task:
db.task(t => {
return t.batch([
t.none(query1),
t.any(query2)
]);
})
.then(data => {
// data[0] = null - result of the first query
// data[1] = [rows...] - result of the second query
callback(null, data); // this will work, but ill-advised
})
.catch(error => {
callback(error, null); // this will work, but ill-advised
});
See also: Chaining Queries.
However, in your case it looks like when you call the successful callback(null, data), it throws an error, which in turn results in it being caught in the following .catch section. To test this, you can change your promise handler like this:
.then(data => {
callback(null, data);
}, error => {
callback(error, null);
});
It should normally throw an error about Promise missing .catch because you threw an error while in .then and there is no corresponding .catch chained below, which you can also check through this code:
.then(data => {
callback(null, data);
}, error => {
callback(error, null);
})
.catch(error => {
// if we are here, it means our callback(null, data) threw an error
});
P.S. You really should learn to use promises properly, and avoid any callbacks altogether. I only provided an example consistent with your own, but in general, converting promises into callbacks is a very bad coding technique.

This is what happens:
callback(null, data) is called within the context of the .then();
async notices that this was the last item of the series, so it calls the final handler (still within the context of the .then());
the final handler throws an error;
because the code runs in the context of .then(), the promise implementation catches the error and calls the .catch();
this calls the callback again;
PoC:
const async = require('async');
async.series([
callback => {
Promise.resolve().then(() => {
callback(null);
}).catch(e => {
callback(e);
});
}
], err => {
throw Error();
})

Have you try to define your function externally:
function onYourFunction() {
console.log('Hi function');
}
and than do:
.then(onYourFunction) //-->(onYourFunction without parentheses )
Unfortunately i don't use pg-promise but i can advise promise
at this point i create all promises that are necessary:
function createPromise(currObj) {
return new Promise(function (resolve, reject) {
currObj.save(function (errSaving, savedObj) {
if(errSaving){
console.log("reject!");
return reject(errSaving, response);
}
console.log('currObj:' + currObj);
return resolve(savedObj);
});
});
}
and then in cascades:
var allPromiseOs = Promise.all(promise1, promise2, promise3);