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JavaScript: How can I insert an Object into an Array of Objects?

I have this script that takes data from a JSON with almost 100 data, then uses this data to bring the weather from an API and after that, inserts this data into an object (using a for for creating my 100 objects), I would like to add the objects that have a temperature > 99 in one array and the ones that have a temperature < 99 into another I have tried this way but doesn't seem to work, sorry if it's a super fool mistake that I can't see, thanks for your help!
This is my script:
async function calcWeather(){
const info = await fetch('../json/data.json')
.then(function(response) {
return response.json()
});
for (var i in info) {
const _idOficina = info[i][0].IdOficina
const _nombreOficina = info[i][0].NombreOficinaSN
const _zona = info[i][0].Zona
const _estado = info[i][0].NombreEstado
const lat = info[i][0].latjson
const long = info[i][0].lonjson
const base = `https://api.openweathermap.org/data/2.5/weather?lat=${lat}&lon=${long}&appid=${api_key}&units=metric&lang=sp`
fetch(base)
.then((responses) => {
return responses.json()
})
.then((data) => {
// console.log(data)
var myObject = {
Id_Oficina: _idOficina,
Latitud: data.coord.lat,
Longitud: data.coord.lon,
Ciudad: data.name,
Estado: _estado,
Zona: _zona,
Nombre_Oficina: _nombreOficina,
Temperatura: data.main.temp,
Descripcion: data.weather[0].description
};
// validation
if (myObject.Temperatura < 99){
var lstValid = [];
function pushValid(){
lstValid.push(myObject[i]);
}
pushValid();
console.log(pushValid())
}
});
}
};

Your array is local, so for every object you create new lstValid array with no previous data. The solution is to create the array before fetching the data or before the loop:
async function calcWeather(){
var lstValid = []; // HERE
const info = await fetch('../json/data.json')
.then(function(response) {
return response.json()
});
var lstValid = []; // OR HERE (ONLY ONE OF THEM)
for (...) {
...
}

You'll probably be best served by creating the array outside of that call since you're clearing it every run. Then simply add your object. Like Trincot's comment, i'm not sure what exactly you're indexing.
async function calcWeather(){
var lstValid = [];
....
if (myObject.Temperatura < 99){
lstValid[someindex] = myObject;
}
else{
lstNotValid[someOtherIndex] = myObject;
}
}

async functions not executing in the correct order inside a map function

I have created an async function that will extra the data from the argument, create a Postgres query based on a data, then did some processing using the retrieved query data. Yet, when I call this function inside a map function, it seemed like it has looped through all the element to extra the data from the argument first before it proceed to the second and the third part, which lead to wrong computation on the second element and onwards(the first element is always correct). I am new to async function, can someone please take at the below code? Thanks!
async function testWeightedScore(test, examData) {
var grade = [];
const testID = examData[test.name];
console.log(testID);
var res = await DefaultPostgresPool().query(
//postgres query based on the score constant
);
var result = res.rows;
for (var i = 0; i < result.length; i++) {
const score = result[i].score;
var weightScore = score * 20;
//more computation
const mid = { "testID": testID, "score": weightScore, more values...};
grade.push(mid);
}
return grade;
}
(async () => {
const examSession = [{"name": "Sally"},{"name": "Bob"},{"name": "Steph"}]
const examData = {
"Sally": 384258,
"Bob": 718239,
"Steph": 349285,
};
var test = [];
examSession.map(async sesion => {
var result = await testWeightedScore(sesion,examData);
let counts = result.reduce((prev, curr) => {
let count = prev.get(curr.testID) || 0;
prev.set(curr.testID, curr.score + count);
return prev;
}, new Map());
let reducedObjArr = [...counts].map(([testID, score]) => {
return {testID, score}
})
console.info(reducedObjArr);
}
);
})();
// The console log printed out all the tokenID first(loop through all the element in examSession ), before it printed out reducedObjArr for each element

The async/await behaviour is that the code pause at await, and do something else (async) until the result of await is provided.
So your code will launch a testWeightedScore, leave at the postgresql query (second await) and in the meantime go to the other entries in your map, log the id, then leave again at the query level.
I didn't read your function in detail however so I am unsure if your function is properly isolated or the order and completion of each call is important.
If you want each test to be fully done one after the other and not in 'parallel', you should do a for loop instead of a map.

React Axios API call with array loop giving wrong order?

I was learning react and doing some axios api call with an array. I did a code on gathering data through coinmarketcap api to learn.
So, my intention was to get the prices from the api with a hardcoded array of cryptocurrency ids and push them into an array of prices. But I ran into a problem with the prices array, as the prices were all jumbled up. I was supposed to get an array in this order
[bitcoinprice, ethereumprice, stellarprice, rippleprice]
but when I ran it in the browser, the prices came randomly and not in this order, sometimes I got my order, sometimes it didn't. I used a button which onClick called the getPrice method. Does anyone know what went wrong with my code? Thanks!
constructor(){
super();
this.state = {
cryptos:["bitcoin","ethereum","stellar","ripple"],
prices:[]
};
this.getPrice = this.getPrice.bind(this);
}
getPrice(){
const cryptos = this.state.cryptos;
console.log(cryptos);
for (var i = 0; i < cryptos.length; i++){
const cryptoUrl = 'https://api.coinmarketcap.com/v1/ticker/' + cryptos[i];
axios.get(cryptoUrl)
.then((response) => {
const data = response.data[0];
console.log(data.price_usd);
this.state.prices.push(data.price_usd);
console.log(this.state.prices);
})
.catch((error) => {
console.log(error);
});
}
}

If you want to receive the data in the order of the asynchronous calls you make, you can use Promise.all, that waits until all the promises of an array get executed and are resolved, returning the values in the order they were executed.
const cryptos = ['bitcoin', 'ethereum', 'stellar', 'ripple'];
const arr = [];
for (var i = 0; i < cryptos.length; i++){
const cryptoUrl = 'https://api.coinmarketcap.com/v1/ticker/' + cryptos[i];
arr.push(axios.get(cryptoUrl));
}
Promise.all(arr).then((response) =>
response.map(res => console.log(res.data[0].name, res.data[0].price_usd))
).catch((err) => console.log(err));

You could use a closure in the for loop to capture the value of i and use it as the index once the data is returned rather than using push:
getPrice(){
const cryptos = this.state.cryptos;
console.log(cryptos);
for (var i = 0; i < cryptos.length; i++) {
const cryptoUrl = 'https://api.coinmarketcap.com/v1/ticker/' + cryptos[i];
(function (x) {
axios.get(cryptoUrl)
.then((response) => {
const data = response.data[0];
console.log(data.price_usd);
var newPrices = this.state.prices;
newPrices[x] = data.price_usd;
this.setState({prices: newPrices});
console.log(this.state.prices);
})
.catch((error) => {
console.log(error);
});
})(i);
}
}

AsyncStorage.getItem returning promise [duplicate]

This question already has answers here:
How do I return the response from an asynchronous call?
(41 answers)
Closed 5 years ago.
So I am trying to get data with AsyncStorage.getItem and then pass it to a function in React-native. but when I do that I get this error "data.filter is not a function" from my function. I think that the problem could be that I am not getting the data but insted a promise.
Constructor:
constructor(props) {
super(props)
const getSectionData = (dataBlob, sectionId) => dataBlob[sectionId];
const getRowData = (dataBlob, sectionId, rowId) => dataBlob[`${rowId}`];
const ds = new ListView.DataSource({
rowHasChanged: (r1, r2) => r1 !== r2,
sectionHeaderHasChanged : (s1, s2) => s1 !== s2,
getSectionData,
getRowData,
});
let data = AsyncStorage.getItem('connections').then((token) => {
token = JSON.parse(token);
return token;
});
const {dataBlob, sectionIds, rowIds} = this.formatData(data);
// Init state
this.state = {
dataSource: ds.cloneWithRowsAndSections(dataBlob, sectionIds, rowIds),
left: true,
center: false,
right: false
}
}
Function:
formatData(data) {
// We're sorting by alphabetically so we need the alphabet
const alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'.split('');
// Need somewhere to store our data
const dataBlob = {};
const sectionIds = [];
const rowIds = [];
// Each section is going to represent a letter in the alphabet so we loop over the alphabet
for (let sectionId = 0; sectionId < alphabet.length; sectionId++) {
// Get the character we're currently looking for
const currentChar = alphabet[sectionId];
// Get users whose first name starts with the current letter
const users = data.filter((user) => user.nickname.toUpperCase().indexOf(currentChar) === 0);
// If there are any users who have a first name starting with the current letter then we'll
// add a new section otherwise we just skip over it
if (users.length > 0) {
// Add a section id to our array so the listview knows that we've got a new section
sectionIds.push(sectionId);
// Store any data we would want to display in the section header. In our case we want to show
// the current character
dataBlob[sectionId] = { character: currentChar };
// Setup a new array that we can store the row ids for this section
rowIds.push([]);
// Loop over the valid users for this section
for (let i = 0; i < users.length; i++) {
// Create a unique row id for the data blob that the listview can use for reference
const rowId = `${sectionId}:${i}`;
// Push the row id to the row ids array. This is what listview will reference to pull
// data from our data blob
rowIds[rowIds.length - 1].push(rowId);
// Store the data we care about for this row
dataBlob[rowId] = users[i];
}
}
}
return { dataBlob, sectionIds, rowIds };
}
So my question is once I have the promise what should I do with it in order to pass it to my function and make this line work const users = data.filter((user) => user.nickname.toUpperCase().indexOf(currentChar) === 0);?

Yea you're not waiting for the promise to resolve, you can either turn the outer function in an async function and await for data to be resolved or whatever you put in the .then gets ran after the promise resolves. Also moving into componentDidMount. You might also want to look into FlatList instead of ListView:
componentDidMount(){
AsyncStorage.getItem('connections').then((token) => {
const token = JSON.parse(token);
const {dataBlob, sectionIds, rowIds} = this.formatData(token);
// Update State
this.setState({
dataSource: ds.cloneWithRowsAndSections(dataBlob, sectionIds, rowIds)
});
});
}

JavaScript multi-level promises skipped .then()

I was having some problem with multi-level of promises. What I tried to do is first get list of receipt items under certain category, then for each receipt item, I get its detail & receipt ID, after I get the receipt ID, I search for the account ID. Then, I get the account details based on account ID. Here is my code:
var query = // get receipt items under certain category
var outerPromise = query.once('value').then(data => {
var promises = [];
var datasetarr = [];
data.forEach(snapshot => {
var itemData = // get receipt item unique push ID
var query = // get details of receipt items
var promise = query.once('value').then(data => {
var itemDetail = // get receipt item detail
if(type == subtype){
var receiptID = itemDetail.receiptID;
var query = // query receipts table by receiptID
return query.once('value').then(data => {
data.forEach(snapshot => {
snapshot.forEach(childSnapshot => {
if(childSnapshot.key == receiptID){
var accountKey = // get accountID
var query = // query accounts table
return query.once('value').then(data => {
var accountDetail = data.val();
var age = accountDetail.age;
var gender = accountDetail.gender;
console.log(age + ' ' + gender);
datasetarr.push({age: age, gender: gender});
});
}
});
});
});
}
});
promises.push(promise);
});
return Promise.all(promises).then(()=> datasetarr);
});
I managed to print out the result from the console.log above. However, when I tried to print out here which is when the promise is done:
outerPromise.then((arr) => {
console.log('promise done');
for(var i = 0; i < arr.length; i++){
console.log(arr[i].age + ' ' + arr[i].gender);
}
});
I get nothing here. The console now is showing 'promise done' first before any other results I printed out above.
How can I do this correctly?

I will provide a more detailed explanation in a couple of hours, I have a prior engagement which means I can't provide details now
First step to a "easy" solution is to make a function to make an array out of a firebase snapshot, so we can use map/concat/filter etc
const snapshotToArray = snapshot => {
const ret = [];
snapshot.forEach(childSnapshot => {
ret.push(childSnapshot);
});
return ret;
};
Now, the code can be written as follows
// get list of receipt items under category
var query // = // get receipt items under certain category
var outerPromise = query.once('value').then(data => {
return Promise.all(snapshotToArray(data).map(snapshot => {
var itemData // = // get receipt item unique push ID
var query // = // get details of receipt items
return query.once('value').then(data => {
var itemDetail // = // get receipt item detail
if(type == subtype){
var receiptID = itemDetail.receiptID;
var query //= // query receipts table by receiptID
return query.once('value').then(data => {
return Promise.all([].concat(...snapshotToArray(data).map(snapshot => {
return snapshotToArray(snapshot).map(childSnapshot => {
if(childSnapshot.key == receiptID){
var accountKey //= // get accountID
var query //= // query accounts table
return query.once('value').then(data => {
var accountDetail = data.val();
var age = accountDetail.age;
var gender = accountDetail.gender;
console.log(age + ' ' + gender);
return({age, gender});
});
}
}).filter(result => !!result);
}).filter(result => !!result)));
});
}
});
})).then([].concat(...results => results.filter(result => !!result)));
});
To explain questions in the comments
[].concat used to add the content of multiple arrays to a new array, i.e
[].concat([1,2,3],[4,5,6]) => [1,2,3,4,5,6]
...snapshotToArray(data).map(etc
... is the spread operator, used as an argument to a function, it takes the iterable and "spreads" it to multiple arguments
console.log(...[1,2,3]) == console.log(1,2,3)
In this case snapshotToArray(data).map returns an array of arrays, to give a console log example
console.log(...[[1,2],[3,4]]) == console.log([1,2], [3,4])
adding the concat
[].concat(...[[1,2],[3,4]]) == [].concat([1,2],[3,4]) == [1,2,3,4]
so it flattens a two level array to a single level, i.e.
console.log(...[[1,2],[3,4]]) == console.log(1,2,3,4)
So in summary, what that code fragment does is flatten a two level array
filter(result => !!result)
simply "filters" out any array elements that are "falsey". As you have this condition
if(childSnapshot.key == receiptID){
if that is false, the result will be undefined for that map - all other results will be an array, and even empty arrays are truthy - that's why the filtering is done so often! There's probably a better way to do all that, but unless you're dealing with literally millions of items, there's no real issue with filtering empty results like this
End result is a flat array with only the Promises returned from the code within