JS Promise inside a method - ecmascript-6

I have a method which signs in a user through firebase with a promise. I have a promise, when its finish, with then, I get the token.
signinUser(email: string, password: string) {
return firebase.auth().signInWithEmailAndPassword(email, password)
.then(
response => {
this.router.navigate(['/']);
firebase.auth().currentUser.getIdToken()
.then(
(token: string) => {
this.token = token
}
)
}
)
.catch(
error => console.log(error)
);
}
Now, I call the method from another file, and I want to do something once the signinUser method is done with its promise
onSignin(form: NgForm) {
const email = form.value.email;
const password = form.value.password;
this.authService.signinUser(email, password)
.then(
res => console.log(res)
)
}
I am getting as res (result) undefined. Why?

You are not returning token from the promise
signinUser(email: string, password: string) {
return firebase.auth().signInWithEmailAndPassword(email, password)
.then((response) => {
this.router.navigate(['/']);
return firebase.auth().currentUser.getIdToken()
.then((token: string) => {
this.token = token
return token;
})
})
.catch(
error => console.log(error)
);
}

Related

cloud function Not all code paths return a value still I am returning all values possible?

any idea why my cloud function is telling my that (Not all code paths return a value) I put a return on the promise at the end also on the if statement yet it is not working, I read about similar issues tried to solve according to them but I still missing part of the puzzle, the error started showing when I wrapped the whole thing with try-catch.
export const createClient = functions.https.onCall(async(data, context) => {
try {
const snapshotCheckBelong = await db.collection('data- main').doc(data.sharedId).get();
const getClient = snapshotCheckBelong.data() ? .clients.filter((el: any) => el.clientId === data.clientId);
const snapshotCheckExist = await db.collection('data-registered-clients').doc(data.sharedId).get();
const checkClient = snapshotCheckExist.data() ? .clients.filter((el: any) => el.clientId === data.clientId);
if (checkClient[0]) {
return {
result: 'Registered client already exisits.'
};
}
if (getClient[0] ? .clientId === data.clientId && checkClient.length === 0) {
const payload = {
user: 'client',
verifiedEmail: false,
createdAt: admin.firestore.Timestamp.now(),
};
let auth = admin
.auth()
.getUserByEmail(context.auth ? .token ? .email!)
.then((user) =>
admin.auth().setCustomUserClaims(user.uid, {
userType: 'client',
premiumUnitll: admin.firestore.Timestamp.fromDate(snapshotCheckBelong.data() ? .premiumUntill)
})
)
.catch((err: any) => {
console.log(err);
});
let setClientData = db
.collection('data-clients')
.doc(context.auth ? .uid!)
.set(payload)
.catch((err: any) => {
console.log(err);
});
let updateRegisteredClients = db
.collection('data-registered-clients')
.doc(data.sharedId)
.update({
clients: admin.firestore.FieldValue.arrayUnion({
clientAccount: context.auth ? .uid,
clientId: data.clientId,
trainerId: data.sharedId
})
})
.catch((err: any) => {
console.log(err);
});
return Promise.all([auth, setClientData, updateRegisteredClients]);
} else {
return null;
}
} catch {
(err: any) => {
console.log(err);
};
}
});
Your catch blocks are not returning anything. If you handle an error with catch, you have to determine what value gets returned to the caller.
I typically prefer sending the error back to the caller, as shown in the documentation on handling errors in callable cloud functions and on the calling client.

LOG {"_U": 0, "_V": 0, "_W": null, "_X": null} inside fetch API

I am getting this error when I console data returned from function that fetch data from back end
{"_U": 0, "_V": 0, "_W": null, "_X": null}
here is below the code:
const events_data = [];
function getvals() {
return fetch('http://PCIP:3000/users/timetable')
.then((response) => response.json())
.then((output) => {
return addData(output, events_data);
})
.catch(error => console.log(error))
}
function addData(data, data2) {
data.map((d) => {
data2.push({
title: d.name,
startTime: genTimeBlock(d.day, d.start_time),
endTime: genTimeBlock(d.day, d.end_time),
location: d.location,
extra_descriptions: [d.extra_descriptions],
});
});
}
const data = getvals();
console.log(data); // the error come from here
I have checked answers here but nothing worked for me
fetch API always returns {“_U”: 0, “_V”: 0, “_W”: null, “_X”: null}
How do I access promise callback value outside of the function?
This is because the fetch promise has not return a response yet,
There two way to solve the issue , first you create another async funciton and use it to await for the response
const events_data = [];
async function getvals() {
return fetch('http://PCIP:3000/users/timetable')
.then((response) => response.json())
.then((output) => {
return addData(output, events_data);
})
.catch(error => console.log(error))
}
function addData(data, data2) {
data.map((d) => {
data2.push({
title: d.name,
startTime: genTimeBlock(d.day, d.start_time),
endTime: genTimeBlock(d.day, d.end_time),
location: d.location,
extra_descriptions: [d.extra_descriptions],
});
});
}
async function waitForResponse() {
let resp = await getvals();
return resp;
}
const data = waitForResponse();
console.log(data); // the error come from here
The other way would be using state hooks, passing the return obj to state hook on response.
Function for API call:
export const getApplication = async (URL, headers) => {
let data;
await fetch.get(URL, headers).then(res => data = res.data).catch(err => err);
return data;
}
You can call the API from anywhere after importing it:
getApplication(`your url`, {
headers: {
Authorization: AUTH_TOKEN,
},
}).then(res => console.log(res)).catch(err => console.log(err));

How to get return values from Async/await function when fetching the data from mySQL in Nodejs

I am fetching some exchange data from DB, then extracting the name of distinct exchanges and passing again into MYSQL query to fetch data from a different table.
The problem I am facing is that async await does not return the value rather just return Promise { }.
Below is the code that I am trying, wondering where I am going wrong.
//Function that fetches the exchanges from DB
const getExchange = () => {
return new Promise((resolve, reject) => {
db.connection.query(`
SELECT *
FROM,
(
SELECT
exchange,
COUNT(pair) as noOfMarkets
FROM ticker_data
) as t
`, (err, resp) => {
if (!err) {
resolve(resp)
} else {
reject(err)
}
})
})
}
// push unique exchanges to an array.
const getExchangesData = async () => {
const allExchanges = await getExchanges();
let exchanges = []
allExchanges.forEach(item => {
let exchange = {
exchange: item.exchange
}
exchanges.push(exchange)
})
return await exchanges
}
// mapping through an array of exchanges and passing to DB query to get data from the DB.
const getSingleExchange = async () => {
const exchanges = await getExchangesData()
await Promise.all(exchanges.map(async (item) => {
db.connection.query(`
SELECT
exchange_rank,
name
volume24hUSD
(
SELECT
volume24hUSD as tradingVolYesterday
FROM exchanges
WHERE name = '${item.exchange}'
AND createdAt >= now() -interval 1 day
AND createdAt < now() -interval 1 day + interval 120 second
LIMIT 1
) volumeDay1
FROM exchanges
WHERE name = '${item.exchange}'
`, (err, resp) => {
if (!err) {
console.log(resp) // getting all the values
let volData = {
name: resp[0].name,
exchange_rank: resp[0].exchange_rank,
icon: resp[0].icon
}
return volData
}
})
}))
}
const data = getSingleExchange()
console.log(data) // returning Promise { <pending> }
Edit
After making changes suggested in an answer, I still have an issue:
//Function that fetches the exchanges from DB
const getExchange = () => {
return new Promise((resolve, reject) => {
db.connection.query(`
SELECT *
FROM,
(
SELECT
exchange,
COUNT(pair) as noOfMarkets
FROM ticker_data
) as t
`, (err, resp) => {
if (!err) {
resolve(resp)
} else {
reject(err)
}
})
})
}
// push unique exchanges to an array.
const getExchangesData = async () => {
const allExchanges = await getExchanges();
let exchanges = []
allExchanges.forEach(item => {
let exchange = {
exchange: item.exchange
}
exchanges.push(exchange)
})
return await exchanges
}
// mapping through an array of exchanges and passing to DB query to get data from the DB.
const getSingleExchange = async () => {
const exchanges = await getExchangesData()
await Promise.all(exchanges.map((item) => {
return new Promise((resolve, reject) => {
db.connection.query(`...`, (err, resp) => {
if (!err) {
resolve(resp)
} else {
reject(err)
}
}).then(resp => {
console.log(resp)
let volData = {
name: resp[0].name,
exchange_rank: resp[0].exchange_rank,
icon: resp[0].icon
}
return volData
})
})
}))
}
getSingleExchange().then(data => {
console.log(data)
});
I now get this error:
(node:30583) UnhandledPromiseRejectionWarning: TypeError: db.connection.query(...).then is not a function
at Promise (/getExchanges.js:217:16)
at new Promise ()
at Promise.all.exchanges.map (/getExchanges.js:145:16)
at Array.map ()
at getSingleExchange (/getExchanges.js:144:33)
The main issue is in this part:
await Promise.all(exchanges.map(async (item) => {
That map callback is not returning anything, and it has no await, so using async makes no sense.
Instead remove async:
await Promise.all(exchanges.map((item) => {
... and return a promise in the callback function, much like you had done in the first function:
return new Promise((resolve, reject) => {
db.connection.query(`...`), (err, resp) => {
if (!err) {
resolve(resp)
} else {
reject(err)
}
})
}).then(resp => {
console.log(resp)
let volData = {
name: resp[0].name,
exchange_rank: resp[0].exchange_rank,
icon: resp[0].icon
}
return volData
});
You would benefit from writing one generic function that promisifies query, so that you don't have to do that new Promise-thing for every single query you need.
Finally, you cannot expect to get an asynchronous result synchronously: async functions do not return the asynchronous result synchronously, but return a promise for it. So your last lines (main code) should still await. So either do this:
(async () => {
const data = await getSingleExchange()
console.log(data)
})(); // immediately executing (async) function expression
Or:
getSingleExchange().then(data => {
console.log(data)
});
NB: doing return await exchanges in the second function makes no sense (exchanges is not a promise), so you can just do return exchanges.

Convert Promise object to JSON in Angular 2

I'm trying to make an HTTP POST and then check the response to see if it fails or succeeds.
The HTTP call looks like this :
doLogin(credentials) {
var header = new Headers();
header.append('Content-Type', 'application/x-www-form-urlencoded');
var body = 'username=' + credentials.username + '&password=' + credentials.password;
return new Promise((resolve, reject) => {
this.http.post(this.url, body, {
headers: header
})
.subscribe(
data => {
resolve(data.json());
},
error => {
resolve(error.json());
}
);
});
}
And the call of this function is the following :
data: Object;
errorMessage: Object;
login($event, username, password) {
this.credentials = {
username: username,
password: password
};
this._loginService.doLogin(this.credentials).then(
result => {
this.data = result;
console.log(this.data);
},
error => {
this.errorMessage = <any>error;
console.log(this.errorMessage);
});
}
On Chrome console, the data is the following :
Object {status: "Login success", token: "eyJhbGciOiJIUzUxMiJ9.eyJzdWIiOiJjcmlzdGkiLCJ1c2VyS…blf1AzZ6KzRWQFNGXCrIeUHRG3Wrk7ZfCou135WmbVa15iYTA"}
How can I access the status in Angular 2? Because if I'm trying to access this.data.status, it's not working.
Should I create a class with the status and token properties?
To answer your question, you can use the response.okboolean that's available in the subscription of the observable from the http.
So based on your code you could pass the data object straight to the promise and inspect data.ok before parsing the data.json.
//...
return new Promise((resolve, reject) => {
this.http.post(this.url, body, {
headers: header
})
.subscribe(resolve,
error => {
reject(error.json());
}
);
});
// then you would have something like this:
this._loginService.doLogin(this.credentials).then(
result => {
if (result.ok) {
this.data = result;
console.log(this.data);
}
},
error => {
this.errorMessage = <any>error;
console.log(this.errorMessage);
})
SUGGESTION
Now, I would recommend getting rid of the promise, as I believe you don't really need it. whoever is consuming your service can just subscribe to the observable returned by the http post, like so:
doLogin(credentials) {
let header = new Headers();
header.append('Content-Type', 'application/x-www-form-urlencoded');
var body = 'username='+credentials.username+'&password='+credentials.password;
return this.http.post(this.url, body, { headers: header });
}
Then, when logging in:
login($event, username, password) {
this.credentials = {
username: username,
password: password
};
this._loginService.doLogin(this.credentials).subscribe(response => {
if (response.ok) { // <== CHECK Response status
this.data = response.json();
console.log(this.data);
} else {
// handle bad request
}
},
error => {
this.errorMessage = <any>error;
console.log(this.errorMessage);
});
}
Hope this helps!
You could do it like this:
data: Object;
errorMessage: Object;
login($event, username, password) {
this.credentials = {
username: username,
password: password
};
this._loginService.doLogin(this.credentials).then(
(result: any) => {
this.data = result;
console.log(this.data);
console.log(this.data.status);
},
error => {
this.errorMessage = <any>error;
console.log(this.errorMessage);
});
}
Set the result to type any. That way you'll be able to access the status, however you could create a class and use rxjs/map within your service to populate the class if you so desire.

Angular 2:Not able to get a token in another component which is stored in local storege

I have one application which include login and home component,
login.service.ts
let body = JSON.stringify(data);
console.log("logged in user",body);
return this._http.post('http://localhost:8080/api/user/authenticate', body, { headers: contentHeaders })
.map(res => res.json())
.map((res) => {
var token1:any = res;
console.log(token1);
if (token1.success) {
localStorage.setItem('auth_token', token1.token);
this.LoggedIn = true;
}
return res.success;
});
}
isLoggedIn() {
return this.LoggedIn;
}
in this service i am getting token in variable token1 and isLogged method contain
constructor(private _http: Http) {
this.LoggedIn = !!localStorage.getItem('auth_token'); }
Login.component.ts
login(event, username, password)
{
this.loginService.login(username, password)
.subscribe(
response => {
this.router.navigate(['/home']);
alert("login successfull");
},
error => {
alert(error.text());
console.log(error.text());
}
);
From this login i can able to authenticate and and its routing to home component,
Home.serice.ts
getClientList()
{
let headers = new Headers();
headers.append('Content-Type', 'application/json');
let authToken = localStorage.getItem('auth_token');
headers.append('X-auth-Token', 'authToken')
return this._http.get('http://localhost:8080/api/v1/client/list?isClient=Y', {headers})
.map(res => res.json())
}
Home.component.ts
onTestGet()
{
this._httpService.getClientList()
.subscribe(
data => this.getData = JSON.stringify(data),
error => alert(error),
() => console.log("finished")
);
}
now question is how can i access that token in home component which is in token1 varible(login) i have tired to getitem token.but i am getting token null.please anybody help me.
thanks in advance
localStorage.getItem('auth_token')
This should work, but you are getting null, because lifecycle of the data different.
I suggest you to use Subject construction for this purpose, especially you already have service with data.
Example:
loginInfo$ = new Subject();
private _logininfo = null;
getLoginData () {
if(!_logininfo) {
this.http..... { this._loginInfo = data;
this.loginInfo$.next(data); }
return this.loginInfo$.first()
}
else return Observable.of(this._logininfo);
}
So now, your service at the same time storage of data and handler for missing login.