Good Afternoon,
I am using the MERN stack to making a simple invoice application.
I have a function that runs 2 forEach() that goes through the invoices in the DB and the Users. if the emails match then it gives the invoices for that user.
When I log DBElement to the console it works, it has the proper data, but when I log test1 to the console (app.get()) it only has one object not both.
// forEach() function
function matchUserAndInvoice(dbInvoices, dbUsers) {
dbInvoices.forEach((DBElement) => {
dbUsers.forEach((userElement) => {
if(DBElement.customer_email === userElement.email){
const arrayNew = [DBElement];
arrayNew.push(DBElement);
app.set('test', arrayNew);
}
})
})
}
// end point that triggers the function and uses the data.
app.get('/test', async (req,res) => {
const invoices = app.get('Invoices');
const users = await fetchUsersFromDB().catch((e) => {console.log(e)});
matchUserAndInvoice(invoices,users,res);
const test1 = await app.get('test');
console.log(test1);
res.json(test1);
})
function matchUserAndInvoice(dbInvoices, dbUsers) {
let newArray = [];
dbInvoices.forEach((DBElement) => {
dbUsers.forEach(async(userElement) => {
if(DBElement.customer_email === userElement.email){
newArray.push(DBElement);
app.set('test', newArray);
}
})
})
}
app.set('test', DBElement); overrides the existing DBElement, so only the last matching DBElement is shown in test1.
If you want to have test correspond to all matching DBElement, you should set it to an array, and then append a new DBElement to the array each time it matches inside the for-loop:
if(DBElement.customer_email === userElement.email){
let newArray = await app.get('test');
newArray.push(DBElement);
app.set('test', newArray);
}
Related
I am trying to make barbershop web app where costumer can see list of free appointments and when they reserve free appointment I want to delete that field from firebase.
I have a collection which represents one barber.
This is how it looks in firebase.
As you see radno_vrijeme is object or map in firebase which contains 6 arrays, and in each array there is list of free working hours.
In my function I am able to do everthing except last line where I need to update firebase collection.
const finishReservation = async () => {
try {
const freeTimeRef = collection(db, `${barber}`);
const q = query(freeTimeRef);
const querySnap = await getDoc(q);
querySnap.forEach(async (doc) => {
const radnoVrijeme = doc.data().radno_vrijeme;
// Find the index of the hour you want to delete
const index = radnoVrijeme["Mon"].indexOf(hour);
// Remove the hour from the array
radnoVrijeme["Mon"].splice(index, 1);
// Update the document in the collection
console.log(radnoVrijeme);
const radnoVrijemeMap = new Map(Object.entries(radnoVrijeme));
await freeTimeRef.update({ radno_vrijeme: radnoVrijemeMap });
});
} catch (error) {
console.log(error);
}
};
I tried to pass it as JSON stringified object, but it didn't work. I always get this error :
"FirebaseError: Expected type 'ya', but it was: a custom Ia object"
When you are trying to fetch multiple documents using a collection reference or query, then you must use getDocs():
const finishReservation = async () => {
try {
const freeTimeRef = collection(db, `${barber}`);
const q = query(freeTimeRef);
const querySnap = await getDocs(q);
const updates = [];
querySnap.forEach((d) => {
const radnoVrijeme = d.data().radno_vrijeme;
const index = radnoVrijeme["Mon"].indexOf(hour);
radnoVrijeme["Mon"].splice(index, 1);
const radnoVrijemeMap = new Map(Object.entries(radnoVrijeme));
updates.push(updateDoc(d.ref, { radno_vrijeme: radnoVrijemeMap }))
});
await Promise.all(updates);
console.log("Documents updated")
} catch (error) {
console.log(error);
}
};
getDoc() is used to fetch a single document using a document reference.
Context
I'm retrieving data from the ESPN API to fetch weekly NFL matchup data. So, I'm making 18 api calls each time I need to fetch this data to account for all 18 weeks in the NFL season. I'm then creating an array with the data I need from the responses to those calls and writing out 18 files that align with each week in the NFL season (week1.json, week2.json, etc.).
Problem
The problem is that when I call my endpoint, I am seeing 2 things intermittently, and not necessarily at the same time:
(1) Some of the json files(week1.json, week2.json, etc.) include only a portion of the expected array. So, instead of 16 objects in the array, I may see only 4, or only 6, etc. Why would I only see a portion of the response data written to the array that's ultimately written to the .json files?
(2) Not all files are written to each time the endpoint is called. So, I may see that only week1-week5's .json files are written. Why aren't all of them updated?
Problem Code
// iterate 18 times
for (let i = 0; i < 18; i++) {
let weekNumber;
weekNumber = i + 1;
const week = fs.readFileSync(`./pickem/week${weekNumber}.json`, 'utf8');
const weekJson = JSON.parse(week);
// empty weekJson.games array
weekJson.games = []
// get all items
axios.get(`https://sports.core.api.espn.com/v2/sports/football/leagues/nfl/seasons/2022/types/2/weeks/${weekNumber}/events?lang=en®ion=us`)
.then(response => {
const schedule = [];
// get all items from response
const items = response.data.items
// console.log(response.data.items)
items.forEach(item => {
// make get call to $ref
axios.get(item.$ref)
.then(response => {
// get name
const name = response.data.name
// get date
const date = response.data.date
// get event id
const eventid = response.data.id
// get team ids
let team1 = response.data.competitions[0].competitors[0].id
let team2 = response.data.competitions[0].competitors[1].id
// create new object
const newObject = {
name: name,
date: date,
eventid: eventid,
team1: team1,
team2: team2
}
// add games for week
weekJson.games.push(newObject);
fs.writeFileSync(`./pickem/week${weekNumber}.json`, JSON.stringify(weekJson));
})
.catch(error => {
console.log(error)
})
})
}).catch(error => {
console.log(error)
})
}
Updated Code
router.get('/getschedules', (req, res) => {
async function writeGames() {
// iterate 18 times
for (let i = 0; i < 18; i++) {
let weekNumber;
weekNumber = i + 1;
const week = fs.readFileSync(`./pickem/week${weekNumber}.json`, 'utf8');
const weekJson = JSON.parse(week);
// empty weekJson.games array
weekJson.games = []
// get all items
// Add await keyword to wait for a week to be processed before going to the next one
await axios.get(`https://sports.core.api.espn.com/v2/sports/football/leagues/nfl/seasons/2022/types/2/weeks/${weekNumber}/events?lang=en®ion=us`)
.then(async (response) => { // add async to be able to use await
const schedule = [];
// get all items from response
const items = response.data.items
console.log(response.data.items)
// Use standard loop to be able to benefit from async/await
for (let item of items) {
// make get call to $ref
// wait for an item to be processed before going to the next one
await axios.get(item.$ref)
.then(response => {
// get name
const name = response.data.name
// get date
const date = response.data.date
// get event id
const eventid = response.data.id
// get team ids
let team1 = response.data.competitions[0].competitors[0].id
let team2 = response.data.competitions[0].competitors[1].id
// create new object
const newObject = {
name: name,
date: date,
eventid: eventid,
team1: team1,
team2: team2
}
// add games for week
weekJson.games.push(newObject);
})
.catch(error => {
console.log(error)
})
}
// moved out of the for loop since you only need to write this once
fs.writeFileSync(`./pickem/week${weekNumber}.json`, JSON.stringify(weekJson));
}).catch(error => {
console.log(error)
})
}
}
writeGames();
})
Your issue might come from the fact that you are looping over an array of item that triggers parallel asynchronous calls and write weekJson before you get the entire data. (But theoretically your code should work if writeSyncFile is really synchronous, maybe there are locks on the file system that prevents node to write properly?)
You could try to make everything sequential and only write weekJson once instead of everytime you go over an item:
EDIT
I updated my original code proposition by keeping parallel calls and it worked for me (it's similar to OP's code but I only write the json file once per week).
Then I tried to run OP's code and it was working fine as well. So this makes me think that the problem isn't from the code itself but rather how it's called. As a pure node script, there doesn't seem to be any issue. But I just noticed that OP is using it server side as the result of an API call.
Having an API write so many JSON concurrently is probably not the best idea (especially if the api is called multiple times almost simultaneously). You could either
just return the games in the response
or precompute the results
or fetch and write them only once then cache the result to be reused
Then I wonder if due to the server context, there is not some kind of timeout since OP said that with my initial solution, only the first week was created.
const axios = require("axios");
const fs = require("fs");
async function writeGames() {
const writeWeekGamesPromises = [];
// iterate 18 times
for (let weekNumber = 1; weekNumber < 19; weekNumber++) {
// give week a default value in case the json file doesn't exist (for repro purpose)
let week = "{}";
try {
week = fs.readFileSync(`./pickem/week${weekNumber}.json`, "utf8");
} catch (e) {
console.log(`error reading week ${weekNumber} json file:`, e);
// file doesn't exist yet
}
const weekJson = JSON.parse(week);
// empty weekJson.games array
const games = [];
weekJson.games = games;
// get all items
// Add await keyword to wait for a week to be processed before going to the next one
writeWeekGamesPromises.push(axios
.get(
`https://sports.core.api.espn.com/v2/sports/football/leagues/nfl/seasons/2022/types/2/weeks/${weekNumber}/events?lang=en®ion=us`
)
.then(async (eventListResponse) => {
// add async to be able to use await
const schedule = [];
console.log(JSON.stringify(eventListResponse.data),'\n');
// get all items from response
const items = eventListResponse.data.items;
// console.log(eventListResponse.data.items); // this seems to be useless since we log the whole data just above
// parallelize calls and wait for all games from a week to be fetched before writing the file
await Promise.all(
items.map((item) => {
// we return the promise so that Promise.all will wait for all games to be pushed before going on writing the file
return axios
.get(item.$ref)
.then((response) => {
// get name, date and eventid
const {name, date, id: eventid} = response.data;
// get team ids
let team1 = response.data.competitions[0].competitors[0].id;
let team2 = response.data.competitions[0].competitors[1].id;
games.push({ name, date, eventid, team1, team2 });
})
.catch((error) => {
console.log(error);
});
})
);
// Now that all game data is ready, write in the file
fs.writeFileSync(
`./pickem/week${weekNumber}.json`,
JSON.stringify(weekJson)
);
})
.catch((error) => {
console.log(error);
}));
}
// Waiting for all games from all weeks to be processed
await Promise.all(writeWeekGamesPromises);
}
async function runAndLogTime() {
const start = Date.now();
await writeGames();
console.log(`took ${(Date.now() - start) / 1000}s to write all json files`);
}
runAndLogTime();
Hi I have exported using data (hawkers collection) using getDocs() from Firebase.
After that I put each hawker data as an object in an array called allStall as shown in the screenshot of the console log below.
Question 1 - How do I access each individual object in my allStall array. I try to use .map() to access each of it, but i am getting nothing.
Do note that I already have data inside my allStall array, see screenshot above.
[Update] map doesn't work in code below because field is stallname not stallName. However, it needs to be async + await if using/call in/from other function.
Question 2 - Why is there [[Prototype]]: Array(0) in my allStall array
export /*Soln add async*/function getAllStall(){
var allStall = [];
try
{
/*Soln add await */getDocs(collection(db, "hawkers")).then((querySnapshot) =>
{
querySnapshot.forEach((doc) =>
{
var stall = doc.data();
var name = stall.stallname;
var category = stall.category;
var description = stall.description;
var stallData = {
stallName:name,
stallCategory:category,
stallDescription:description
};
allStall.push(stallData);
});});
console.log(allStall);
//Unable to access individual object in Array of objects
allStall.map(stall =>{console.log(stall.stallName);});}
catch (e) {console.error("Error get all document: ", e);}
return allStall;
}
In my main js file, i did the following:
useEffect(/*Soln add await*/() =>
{
getAllStall();
/*Soln:replace the statement above with the code below
const allStall = await getAllStall();
allStall.map((stall)=>console.log(stall.stallname));
*/
}
);
You are getting nothing because allStall is empty since you are not waiting for the promise to be fullfilled
try this
export const getAllStall = () => getDocs(collection(db, "hawkers"))
.then((querySnapshot) =>
querySnapshot.map((doc) =>
{
const {stallName, category, description} = doc.data();
return {
stallName:name,
stallCategory:category,
stallDescription:description
};
});
)
try to change use effect like this
useEffect(async () =>
{
const allStats = await getAllStall();
console.log(allStats)
allStats.forEach(console.log)
}
);
A very big thanks to R4ncid, you have been an inspiration!
And thank you all who commented below!
I managed to get it done with async and await. Latest update, I figure out what's wrong with my previous code too. I commented the solution in my question, which is adding the async to the function and await to getDocs.
Also map doesn't work in code above because field is stallname not stallName. However, it needs to be async + await if using in/calling from other function.
Helper function
export async function getAllStall(){
const querySnapshot = await getDocs(collection(db, "hawkers"));
var allStall = [];
querySnapshot.forEach(doc =>
{
var stall = doc.data();
var name = stall.stallname;
var category = stall.category;
var description = stall.description;
var stallData = {
stallName:name,
stallCategory:category,
stallDescription:description
};
allStall.push(stall);
}
);
return allStall;
}
Main JS file
useEffect(async () =>
{
const allStall = await getAllStall();
allStall.map((stall)=>console.log(stall.stallname));
}
);
Hurray
So I'm working on a project where I'm making a call to a database to retrieve the data stored there. This data comes as an array. here is the code:
const allLogins = await Login.find().sort("name");
const token = req.header("x-auth-token");
const user = jwt.verify(token, config.get("jwtPrivateKey"));
const logins = allLogins
.filter((login) => login.userId === user._id)
.map((login) => {
login.password = decrypt(login.password);
});
If I call a console.log after the decrypt has been run I see that it has been completed correctly. The issue I have is if I console.log(logins) it says it is an array of two items that are both undefined. If instead I run it like this...
const allLogins = await Login.find().sort("name");
const token = req.header("x-auth-token");
const user = jwt.verify(token, config.get("jwtPrivateKey"));
let logins = allLogins.filter((login) => login.userId === user._id);
logins.map((login) => {
login.password = decrypt(login.password);
});
Then it works as it should. I'm not sure why the first set of code doesn't work and why the second set does work.
Any help would be appreciated!
Basic :
array. filter - accept a callback and call back return boolean (that match our criteria)
array.map - accept a callback and call back return transformed object
In the second working example:
logins.map((login) => {
// note: logins is iterated but not assigned to logins back
// so accessing login is working
login.password = decrypt(login.password); // map should return data
+ return login; // if we update all code will work
});
Now coming to first example:
const logins = allLogins
.filter((login) => login.userId === user._id)
.map((login) => {
login.password = decrypt(login.password);
+ return login; // this will fix the issue
});
I'm trying to iterate and print out in order an array in Javascript that contains the title of 2 events that I obtained from doing web scraping to a website but it prints out in disorder. I know Javascript is asynchronous but I'm new in this world of asynchronism. How can I implement the loop for to print the array in order and give customized info?
agent.add('...') is like console.log('...'). I'm doing a chatbot with DialogFlow and NodeJs 8 but that's not important at this moment. I used console.log() in the return just for debug.
I tried the next:
async function printEvent(event){
agent.add(event)
}
async function runLoop(eventsTitles){
for (let i = 0; i<eventsTitles.length; i++){
aux = await printEvent(eventsTitles[i])
}
}
But i got this error error Unexpected await inside a loop no-await-in-loop
async function showEvents(agent) {
const cheerio = require('cheerio');
const rp = require('request-promise');
const options = {
uri: 'https://www.utb.edu.co/eventos',
transform: function (body) {
return cheerio.load(body);
}
}
return rp(options)
.then($ => {
//** HERE START THE PROBLEM**
var eventsTitles = [] // array of event's titles
agent.add(`This mont we have these events available: \n`)
$('.product-title').each(function (i, elem) {
var event = $(this).text()
eventsTitles.push(event)
})
agent.add(`${eventsTitles}`) // The array prints out in order but if i iterate it, it prints out in disorder.
// *** IMPLEMENT LOOP FOR ***
agent.add(`To obtain more info click on this link https://www.utb.edu.co/eventos`)
return console.log(`Show available events`);
}).catch(err => {
agent.add(`${err}`)
return console.log(err)
})
}
I would like to always print out Event's title #1 and after Event's title #2. Something like this:
events titles.forEach((index,event) => {
agent.add(`${index}. ${event}`) // remember this is like console.log(`${index}. ${event}`)
})
Thanks for any help and explanation!
There no async case here but if you still face difficultly than use this loop
for (let index = 0; index < eventsTitles.length; index++) {
const element = eventsTitles[index];
agent.add(${index}. ${element})
}