Develop Reference

removing an object from firestore 9 array using arrayRemove()?

I am trying to remove an object from array in in firestore, but encountered an obstacle what are the requirement or the reference to do the removal ? does one key value in the object sufficient to do the remove or should the object by identical to the one that is getting removed ?
const deleteWeek = async () => {
const docRef = doc(db, 'Weeks', id);
await updateDoc(docRef, {
weeks: arrayRemove({
weekId: '7518005f-7b10-44b6-8e0a-5e41081ee064',
}),
});
};
deleteWeek();
}
however week in data base looks like this
{name ,"Week 2"
days : [/*data all kinds*/]
weekId : "7518005f-7b10-44b6-8e0a-5e41081ee064"}

If it's an array of object, then you need to know the whole object to use arrayRemove() For example, if the a document looks like this:
{
...data
weeks: [
{
name: "Week 2",
days: [/*data all kinds*/]
weekId: "7518005f-7b10-44b6-8e0a-5e41081ee064"}
}
]
}
You'll have to pass the entire week object in arrayRemove(). It might be better to store such data in sub-collections instead so you can query/delete a specific one.

Since there is no function in firestore to delete only a element in array, you need to make arrayRemove refer to the same object you want to delete, then create a new object and insert it with arrayUnion method
in my case, i use to below
const { leave,date,email } = req.body;
const attendanceRef = admin.firestore().collection('Attendance').doc(`${email}`);
const attendanceData = await attendanceRef.get();
const attendanceRecord = attendanceData.data().attendance;
const removeTarget = attendanceRecord.find((item) => item.date === date);
await attendanceRef.update({
attendance: admin.firestore.FieldValue.arrayRemove(removeTarget),
})
const obj = {
...removeTarget,
"leave": leave,
}
await attendanceRef.set({
attendance: admin.firestore.FieldValue.arrayUnion(obj),
},{ merge: true })
const newAttendance = await attendanceRef.get();
const newAttendanceRecord = newAttendance.data().attendance;
return await res.json({
message: '퇴근시간이 저장되었습니다.',
attendance:newAttendanceRecord
});
after update, it maybe if error occured.
if error occured, you need all working cancel.
this case, you may want to use batch method
const admin = require('firebase-admin');
module.exports = async function(req,res) {
const { leave,date,email } = req.body;
const batch = admin.firestore().batch();
const attendanceRef = admin.firestore().collection('Attendance').doc(`${email}`);
const attendanceData = await attendanceRef.get();
const attendanceRecord = attendanceData.data().attendance;
const removeTarget = attendanceRecord.find((item) => item.date === date);
// await attendanceRef.update({
// attendance: admin.firestore.FieldValue.arrayRemove(removeTarget),
// })
batch.update(
attendanceRef,{ attendance: admin.firestore.FieldValue.arrayRemove(removeTarget) }
)
const obj = {
...removeTarget,
"leave": leave,
}
// await attendanceRef.set({
// attendance: admin.firestore.FieldValue.arrayUnion(obj),
// },{ merge: true })
batch.set(
attendanceRef, { attendance: admin.firestore.FieldValue.arrayUnion(obj) },{ merge: true }
)
await batch.commit();
const newAttendance = await attendanceRef.get();
const newAttendanceRecord = newAttendance.data().attendance;
return await res.json({message: '퇴근시간이 저장되었습니다.',attendance:newAttendanceRecord});
}
hope help this for you

Filter related models by Sequelize

I have two models in my aplication, Delivery and DeliveryProblem.
DeliveryProblem has a PK (delivery_id) from Delivery:
static associate(models) {
this.belongsTo(models.Delivery, {
foreignKey: 'delivery_id',
as: 'delivery',
});
}
I need select all Deliveries that have a Delivery Problem.
In my Controller, a have the follow method:
async index(req, res) {
const response = await DeliveryProblem.findAll({
order: ['id'],
attributes: ['delivery_id'],
});
// Filter all Deliveries with problem
const ids = [...new Set(response.map((x) => x.delivery_id))];
const deliveries = Delivery.findAll({
where: , // <<< How can I filter ?
order: ['id'],
});
return res.json(deliveries);
}

const Sequelize = require('sequelize')
const Op = Sequelize.Op
...
// Filter all Deliveries with problem
const ids = [...new Set(response.map((x) => x.delivery_id))];
const deliveries = Delivery.findAll({
where: {
id: {
[Op.in]: ids
}
},
order: ['id'],
});

How to distinct query and get last data date? (parse server)

like js code
when I do this
it will query up to 1000 times,
can it query once?
const promises = idList.map(async id => {
const query = new Parse.Query("results");
query.equalTo("id", id);
query.descending("createdAt");
query.first()
});
const prPool = await Promise.all(promises);

You need to use aggregate. It would be something like this:
const pipeline = [
{ match: { id: id } },
{ sort: { createdAt: -1 } },
{ group: { objectId: '$id', lastCreatedAt: { $first: '$createdAt' } } }
];
const query = new Parse.Query('results');
const prPool = await query.aggregate(pipeline);

How to run fetch() in a loop?

I am new to nodejs and promise based request. I want to fetch the data from a remote server in a loop, and then create a JSON object from all fetched data.
const fetch = require('node-fetch');
const users = [];
const ids = await fetch('https://remote-server.com/ids.json');
console.log(ids);
// [1,2,3]
ids.forEach(id => {
var user = await fetch(`https://remote-server.com/user/${id}.json`);
users.push(user);
});
console.log(users);
expected output
[
{
name: 'user 1',
city: 'abc'
},
{
name: 'user 2',
city: 'pqr'
},
{
name: 'user 3',
city: 'xyz'
}
]

So to launch in parallel:
const ids = await fetch('https://remote-server.com/ids.json');
const userPromises = ids.map(id => fetch(`https://remote-server.com/user/${id}.json`));
const users = await Promise.all(userPromises);
to launch in sequence:
const users = [];
const ids = await fetch('https://remote-server.com/ids.json');
for(const id of ids){
const user = await fetch(`https://remote-server.com/user/${id}.json`);
users.push(user);
}

You forgot to add async in the forEach:
ids.forEach(async (id) => { // your promise is in another function now, so you must specify async to use await
var user = await fetch(`https://remote-server.com/user/${id}.json`);
users.push(user);
});

How to query a model with different attributes

I'm building an app in Express and using Postgres for my database, Sequelize for ORM.
In my database each Post can have one of the 5 types, 1, 2, 3, 4, 5.
I want to show the amount of all the posts by type.
router.route('/post).get(async (req, res) => {
const postOne = await Post.findAll({
where: {
state: 1
}
});
const postTwo = await Post.findAll({
where: {
state: 2
}
});
res.send({ postOne: postOne.length, postTwo: postTwo.length });
I can write like this for all of the 5 types, but I was wondering if there was any shorter way to do it so that I don't have to write the same code 5 times.
Thanks!

const getPostWithType = (type) => Post.findAll({
where: {
state: type
}
});
Now you can await getPostWithType(1) instead. Or even better:
const postTypes = [1,2,3,4,5];
const allPosts = await Promise.all(postTypes.map(getPostWithType));
// allPosts is now an array with the results. You can map it again to get the lengths
const allPostLengths = allPosts.map(p => p.length);

what about using an array? Like below...
let promiseArray = [];
for (let i = 1; i <= 5; i++) {
let promise = Post.findAll({
where: {
state: i
}
});
promiseArray.push(promise);
}
Promise.all(promiseArray).then(function(response) {
//Do whatever...
});