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Print list of values from various arrays JavaScript

I am attempting to gather values from my API to input them into a graph. With that, I am looking to get an array of just the value 'date'. I have queried through the data to get the following printed:
That is through the following code:
return {
props: {
data: data
}
}
console.log([[props][0]['data']])
How do I simply get the 336 'date' values in an array? For example, [20210112, 20210111, 20210110...] I could not find any documentation to help with this issue, and I would appreciate any input.

You can map the data items and inside the callback, you can destructure the date field and return its value.
const data = [
{ date: 20210101 }, { date: 20210102 }, { date: 20210103 },
{ date: 20210104 }, { date: 20210104 }, { date: 20210105 }
];
const datesOnly = data.map(({ date }) => date);
console.log(datesOnly);
Destructuring can be simplified as:
const item = { date: 20210101 };
// Left-hand of assignment: Variables that match the field to be extracted
const { date } = item;
console.log(date);
The variables can also be renamed:
const item = { date: 20210101 };
const { date: myDate } = item;
console.log(myDate);
Update
If you want multiple field, you can map a new object.
const data = [
{ date: 20210101, eg: 1 }, { date: 20210102, eg: 2 }, { date: 20210103, eg: 3 },
{ date: 20210104, eg: 4 }, { date: 20210104, eg: 5 }, { date: 20210105, eg: 6 }
];
const datesEgsOnly = data.map(({ date }) => date);
const egsOnly = data.map(({ eg }) => eg);
const datesAndEgsOnly = data.map(({ date, eg }) => ({ date, eg }));
console.log(datesEgsOnly);
console.log(egsOnly);
console.log(datesAndEgsOnly);
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How to get unique date values from object array

I need to get all unique days of multiple date values in the format DD.MM.. In this example data, there are two values for the 24th of december:
const data = [
{ date: ISODate("2019-12-24T03:24:00Z") },
{ date: ISODate("2019-12-24T04:56:00Z") },
{ date: ISODate("2019-12-25T02:34:00Z") },
{ date: ISODate("2019-12-26T01:23:00Z") }
]
So the result should be
const result = [
'24.12.',
'25.12.',
'26.12.'
]
So first of all I'll map my data and split the values only for the dates:
const dates = data.map(d => d.date.toString().split('T')[0])
But how do I get the unique values and change the output format?
Update
I came up with this, but it looks very complicated...
data.map(d => {
const dateSplit = d.date.toString().split('T')[0].split('-')
return dateSplit[2] + '.' + dateSplit[1] + '.'
})
.filter((value, index, self) {
return self.indexOf(value) === index
})

It seems that ISODate returns a standard JS Date object. You can use Date.getDate() to get the day, and Date.getMonth() to get the month (0 based, so we need to add 1):
const data = [
{ date: new Date('2019-12-24T03:24:00Z') },
{ date: new Date('2019-12-24T04:56:00Z') },
{ date: new Date('2019-12-25T02:34:00Z') },
{ date: new Date('2019-12-26T01:23:00Z') }
]
const result = [...new Set(data.map(({ date: d }) =>
`${d.getDate()}.${d.getMonth() + 1}.`
))]
console.log(result)
Previous answer:
Use a regular expression to match the month and the day, and assign them to consts using destructuring. Assemble the string using template literal. Remove duplicates by assigning the values to a Set, and then spreading back to an array.
Note: Since I don't have access to the ISODate, I've removed it. I left .toString() although it's not needed in this example, but will be needed when used with ISODate.
const data = [
{ date: '2019-12-24T03:24:00Z' },
{ date: '2019-12-24T04:56:00Z' },
{ date: '2019-12-25T02:34:00Z' },
{ date: '2019-12-26T01:23:00Z' }
]
const pattern = /-([0-9]{2})-([0-9]{2})T/
const result = [...new Set(data.map(d => {
const [, mon, day] = d.date.toString().match(pattern)
return `${day}.${mon}.`;
}))]
console.log(result)

Use .filter() to filter through only values that are the first of their value.
//temporary function
const ISODate = (d) => d;
const data = [{
date: ISODate("2019-12-24T03:24:00Z")
},
{
date: ISODate("2019-12-24T04:56:00Z")
},
{
date: ISODate("2019-12-25T02:34:00Z")
},
{
date: ISODate("2019-12-26T01:23:00Z")
}
]
const dates = data.map(d => d.date.toString().split('T')[0].split("-").slice(1, 3).reverse().join(".") + ".")
console.log(dates.filter((v, i, a) => a.indexOf(v) === i));

You can do this pretty easily by using Array.reduce. Note that I converted ISODate to be Date since I don't have that class, but it should be the same concept.
const data = [
{ date: new Date("2019-12-24T03:24:00Z") },
{ date: new Date("2019-12-24T04:56:00Z") },
{ date: new Date("2019-12-25T02:34:00Z") },
{ date: new Date("2019-12-26T01:23:00Z") }
];
const result = data.reduce( (acc, curr) => {
if (acc.length > 0) {
const hasDate = acc.find(d => d.date.getMonth() === curr.date.getMonth() && d.date.getDate() === curr.date.getDate());
if (!hasDate) { acc.push(curr); }
} else {
acc.push(curr);
}
return acc;
}, []);
console.log(result);

I would use the uniq function in the Underscore.js library:
const data = [
{ date: ISODate("2019-12-24T03:24:00Z") },
{ date: ISODate("2019-12-24T04:56:00Z") },
{ date: ISODate("2019-12-25T02:34:00Z") },
{ date: ISODate("2019-12-26T01:23:00Z") }
];
let dates = _.uniq(data.map(d => d.date.toString().split('T')[0]));

A nice considerable way is:
const array = [1, 2, 6, 5,5, 5, 3, 7, 8];
const uniqueKeys = array.reduce((hashMap, value) => {
if (!hashMap[value]) {
hashMap[value] = true;
}
return hashMap;
}, {});
const uniqueValues = Object.keys(uniqueKeys);
console.log(uniqueValues);
It is nice because it iterates the array once, instead of x * x (a.k.a log(n) instead of log(n^2) as with .filter() example
const array = [1, 2, 6, 5,5, 5, 3, 7, 8];
const uniqueKeys = array.reduce((hashMap, value) => {
if (!hashMap[value]) {
hashMap[value] = true;
}
return hashMap;
}, {});
const uniqueValues = Object.keys(uniqueKeys);
console.log(uniqueValues);

How can I format my array of objects in javascript?

Need to format my array of objects to have a nested object.
Tried using map, and reduce. Can't seem to get the formatting correct.
Currently getting this.
[
{
"date": "2019-10-01T00:00:00Z",
"total": 20
}
]
Need it to be in this format.
[
{
name: 'Total Call Volume',
data: {
'2019-01-01 00:00:00 -0800': 0,
'2019-01-01 00:00:00 -0800': 88,
}
}
]
var arr = this.$store.state.aggregatedCallVolumeData;
var mapData = arr.map(item => ({
date: item.startTime,
total: item.dataValues.TOTAL_CALL_VOLUME
}));
var data = mapData.reduce((acc, value) => {
acc[value.date] = acc[value.date] ? acc[value.date] : [];
acc[value.date] ? acc[value.date].push(value.total) : [value.total];
return acc;
}, {});
let result = Object.entries(data).map(d => ({ id: d[0] + ':' + d[1] }) );
console.log(result)
console output is
0: {id: "2019-10-27T00:00:00Z:0"}
1: {id: "2019-10-28T00:00:00Z:88"}

arr.reduce((obj, item) => {
obj.data[item.date] = item.total;
return obj;
}, {
name: 'Total Call Volume',
data: {}
})
something like that. You might need to switch around the 'obj' and 'item' param. Basically the obj param is the second argument in the reduce function. So the obj is that base object I added at the end, and the 'item' param is each item in the array. So we loop and keep adding the values on to the 'obj' and return it for the next loop to add onto

JavaScript: Compare dates in an array and sum the "price" for each month/year

I have a json file with multiple transactions with a date and a price attribute. Now I want to compare the dates and if they are in the same month and year I want to sum up the prices.
JSON:
transactions: [
{
date: "2017-11-17",
price: "28",
},
{
...
}
JavaScript:
request.onload = function() {
for(const transaction of request.response.transactions) {
let year = new Date(transaction.date).getFullYear();
let month = new Date(transaction.date).getMonth();
console.log(year + ' ' + month); // output: 2017-11 ...
}
};
I tried to loop over the json object but I struggle to find a solution to compare the dates.

Edit: Edited example with Object.assign instead of Object spread.
You'll need to use reduce to sum the prices. See comments for details.
const transactions = [{
date: "2017-11-17",
price: "28",
},
{
date: "2017-12-17",
price: "23",
},
{
date: "2017-11-17",
price: "12",
},
{
date: "2017-10-17",
price: "55",
},
{
date: "2017-11-17",
price: "09",
},
];
const sumTransactions = (transactions) => {
const summed = transactions.reduce((acc, current) => {
// Get the current date object
const date = new Date(current.date);
// Create your key/identifier
const key = `${date.getFullYear()}-${date.getMonth() + 1}`;
// Retreive the previous price from the accumulator
const previousPrice = acc[key]; // Might also return undefined
// Create your temp current price value, and be sure to deal with numbers.
let currentPrice = Number(current.price);
// If you had a previous value (and not undefined)
if (previousPrice) {
// Add it to our value
currentPrice += Number(previousPrice);
}
// Return the future accumulator value
return Object.assign(acc, {
[key]: currentPrice, // new values will overwrite same old values
})
}, {})
// Once we have all values, get the dates, and sort them (default: earlier first)
// Return an array of each value from the summed object to our sortedArray
const sortedArray = Object.keys(summed).sort().map((val) => {
return summed[val];
});
console.log("sortedArray", sortedArray);
};
sumTransactions(transactions);

I experimented a bit and came up with this solution:
var transactions = [
{
date: "2017-11-17",
price: "28",
},
{
date: "2017-12-17",
price: "22",
},
{
date: "2017-12-17",
price: "20",
}
]
var sumedUpDates = [];
var prices = [];
function isDateSumedUp(date) {
return sumedUpDates.indexOf(date.substring(0, 7)) !== -1;
}
function sumUpDate(date) {
var sum = 0;
transactions.forEach(t => {
if(t.date.substring(0, 7) === date.substring(0, 7)) {
sum += parseInt(t.price);
}
});
sumedUpDates.push(date.substring(0, 7));
prices.push(sum);
}
transactions.forEach(t => {
if(!isDateSumedUp(t.date)) {
sumUpDate(t.date);
}
});
var obj = {};
sumedUpDates.forEach((d, i) => obj[d] = prices[i]);
console.log(obj);

This solutions uses map to format your dates into year/month format for each object entry and then reduce to sum them by those separated dates.
const transactions = [
{date:"2017-11-17", price: "28",},
{date:"2017-12-17", price: "28",},
{date:"2017-11-17", price: "20",},
{date:"2017-12-17", price: "2",},
{date:"2017-11-17", price: "58",},
{date:"2017-11-17", price: "8",},
{date:"2017-10-17", price: "30",},
{date:"2018-11-17", price: "1",},
];
const mapper = single => {
let d = single.date.split('-');
let p = Number(single.price);
return { year: d[0], month: d[1], price: p };
}
const reducer = (group, current) => {
let i = group.findIndex(single => (single.year == current.year && single.month == current.month));
if (i == -1) {
return [ ...group, current ];
}
group[i].price += current.price;
return group;
};
const sumPrices = transactions.map(mapper).reduce(reducer, []);
console.log(sumPrices);

var array = [];
for (var i = 0; i < transactions.length; i++) {
var date = new Date(transactions[i].date);
var ym = date.getFullYear() + "-" + date.getMonth();
if (array[ym] == null) {
array[ym] = 0;
}
array[ym] += parseInt(transactions[i].price);
}
With this data
var transactions = [{
date: "2017-11-17",
price: "28",
},
{
date: "2017-12-17",
price: "5",
},
{
date: "2016-02-17",
price: "28",
},
{
date: "2015-11-17",
price: "25",
},
{
date: "2016-02-17",
price: "12",
},
{
date: "2017-11-17",
price: "50",
}
];
This will give you the sum of all of the year-months duplicates like this :
[
2017-10: 78,
2017-11: 5,
2016-1: 40,
2015-10: 25
]

Another solution is reduce:
var transactions = [
{date: "2017-11-17",price: "28"},
{date: "2017-12-17",price: "22"},
{date: "2017-12-17",price: "20"}
];
var result = transactions.reduce(function(acc, obj) {
var key = obj.date.substr(0,7);
acc[key] = (acc[key] || 0) + +obj.price;
return acc;
}, Object.create(null));
console.log(result);

how can I convert Javascript List of properties to List of objects

I have a list of properties like this
[{"ID":"0"},{"Day":""},{"Time":""},{"Type":"Both"},{"Status":"false"},
{"ID":"0"},{"Day":""},{"Time":""},{"Type":"Both"},{"Status":"false"}]
I would like to convert them to something like this
[{"ID":"0","Day":"","Time":"","Type":"Both","Status":"false"},
{"ID":"0","Day":"","Time":"","Type":"Both","Status":"false"}]
This is one problem that i face nearly everytime converting a form to json and submitting it to a controller with complex type.

You could check if an object contains the key ID and build a new object with all following objects.
var data = [{ ID: "0" }, { Day: "" }, { Time: "" }, { Type: "Both" }, { Status: "false" }, { ID: "0" }, { Day: "" }, { Time: "" }, { Type: "Both" }, { Status: "false" }],
result = data.reduce(function (r, o) {
if ('ID' in o) {
r.push(Object.assign({}, o));
} else {
Object.assign(r[r.length - 1], o);
}
return r;
}, []);
console.log(result);
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That is one weird input,..
With the following I'm assuming there is always an ID, and it comes first. As that data structure has no way of splitting the properties.
var a = [{"ID":"0"},{"Day":""},{"Time":""},{"Type":"Both"},{"Status":"false"},
{"ID":"0"},{"Day":""},{"Time":""},{"Type":"Both"},{"Status":"false"}];
var
ret = [],
c = null;
a.forEach((r) => {
if (r.ID) { c = {}; ret.push(c); }
let k = Object.keys(r)[0];
c[k] = r[k];
});
console.log(ret);