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How to extract numbers from an array [closed]

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So basically I have an array of ids and I want to return only a simple array which I want to look like this
*[1,2,3]*
instead of
*[0:[1] , 1:[2]]*
Is there any way to do it
Code
const usersWhoHavePurchasedYourCourses = usersWhoHaveTokens.filter(
(user1: any) => {
return user1.tokens
?.map((token: any) => parseInt(token.course_id))
.includes(user.courses?.map((course: any) => course.id));
});
The output looks like this
output
As I said I don`t want to return this kind of output.

Edit
In attempting to reverse-engineer your logic, wouldn't you want to filter by checking if a user has at least one course? I recommend using Array.prototype.some as your filter result.
const user = { courses: [{ id: 1 }, { id: 2 }] };
const usersWhoHaveTokens = [
{ id: 1, tokens: [{ course_id: '1' }] },
{ id: 2, tokens: [{ course_id: '2' }] },
{ id: 3, tokens: [{ course_id: '3' }] },
];
// Compute the set, for faster processing
const userCourseIds = new Set(user.courses.map((course) => course.id));
const usersWhoHavePurchasedYourCourses = usersWhoHaveTokens
.filter(({ tokens }) => tokens
.some((token) => userCourseIds.has(parseInt(token.course_id))))
.map(({ id }) => id);
console.log(usersWhoHavePurchasedYourCourses); // [1, 2]
Original response
If you object is an 'object' type, you will need to transform it into an array, and then flatten it.
const
obj = { 0: [1], 1: [2] },
arr = Object.values(obj).flat();
console.log(JSON.stringify(arr)); // [1, 2]
If you want to preserve indices:
const
obj = { 1: [2], 5: [6] },
arr = Object.entries(obj).reduce((acc, [index, value]) => {
acc[+index] = value;
return acc;
}, []).map(([value]) => value);
console.log(JSON.stringify(arr)); // [null, 2, null, null, null, 6]

Combine Objects in a js array without overwriting them [closed]

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i have an array like below
[
{
"202229": "8.418"
},
{
"202229": null
},
{
"202229": null
},
{
"202230": "10.713"
},
{
"202230": "0.859"
}
]
i want to convert it to below structure
[
{
"202229": "8.418",
"202229": null,
"202229": null,
"202230": "10.713",
"202230": "0.859"
}
]
Note that values are not overwritten and keys "202229" etc are dynamic . I tried using reduce methods but i couldn't get it in this format . Any help would be appreciated . Thanks

You could disperse the keys to various objects.
const
data = [{ 202229: "8.418" }, { 202229: null }, { 202229: null }, { 202230: "10.713" }, { 202230: "0.859" }, { 202231: "0.503" }, { 202231: null }],
result = data.reduce((r, o) => {
Object.entries(o).forEach(([k, v]) => {
let i = 0;
while (k in (r[i] ??= {})) i++;
r[i][k] = v;
});
return r;
}, []);
console.log(result);
.as-console-wrapper { max-height: 100% !important; top: 0; }

Dynamically assign object values to variable in JavaScript [closed]

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I need to assign the values of the below array of objects into defined variables which are initialized as empty strings.
What I have tried up until now:
const transaction = [{
number: 10,
value: "Ten"
},
{
number: 20,
value: "Twenty"
},
];
let transactionOneValue, transactionTwoValue, transactionOneNumber, transactionTwoNumber = "";
if (transaction.length > 0) {
transaction.forEach(item => {
[transactionOneNumber, transactionTwoNumber].forEach(num => num = item.number);
[transactionOneValue, transactionTwoValue].forEach(val => val = item.value);
});
}
Expected output:
transactionOneValue = "Ten",
transactionTwoValue = "Twenty",
transactionOneNumber = 10,
transactionTwoNumber = 20
How can I do it?

Destructuring seems to be simplest approach here, but I don't see how this would be useful. Creating separate variables for every item in a list isn't scalable.
let [
{number: transactionOneNumber, value: transactionOneValue},
{number: transactionTwoNumber, value: transactionTwoValue}
] = transaction

const transaction = [{
number: 10,
value: "Ten"
},
{
number: 20,
value: "Twenty"
},
];
let transactions = [];
if (transaction.length > 0) {
transaction.map((value, index, array) => {
for(x of Object.values(value)) {
transactions.push(x);
}
})
}
let transactionOneNumber = transactions[0],
transactionOneValue = transactions[1],
transactionTwoNumber = transactions[2],
transactionTwoValue = transactions[3];
console.log(transactionOneNumber);
console.log(transactionOneValue);
console.log(transactionTwoNumber);
console.log(transactionTwoValue);
output:
10
"Ten"
20
"Twenty"
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/values

How to merge two array and assign each iteration a key [closed]

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I have two array
arr1 = ["google.com", "none", "Twitter", "Facebook"]
arr2 = [6, 25, 1, 8]
Then my expected output would be like this
newArr = [
{
'medium': 'www.google.com',
'key': 6
},
{
'medium': 'none',
'key': 25
},
{
'medium': 'Twitter',
'key': 1
},
{
'medium': 'Facebook',
'key': 8
}
];
I have tried something like this but did not get the expected output
const result = arr1.reduce(function(result, field, index) {
result[arr2[index]] = field;
return result;
});
How can I achieve the output? Thanks.

You could do a map with index
const arr1 = ["google.com", "none", "Twitter", "Facebook"]
const arr2 = [6, 25, 1, 8]
const res = arr1.map((_, index) => ({
medium: arr1[index],
key: arr2[index],
}))
console.log(res)

This should work assuming arr1 and arr2 length always equal
function combineTwoArrays (arr1, arr2){
let result = []
for (let i = 0; i< arr1.length; i++){
result.push({
medium: arr1[i],
key: arr2[i]
})
}
return result
}

How to remove key array in javascript by keep default value [closed]

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Hi I want to delete key in array
here is my array
const data = [ { id: "2" } , { id: "4" } ]
I want ouput
['2','4']
here is what i try
data.map(function(item) {
//I return only item.id but output still not change
return item.id
})

That's because .map() method returns a new array, it does not alternate the current array. You need to store the returned array in another variable to get the required output like:
const data = [ { id: "2" } , { id: "4" } ]
const res = data.map(x => x.id)
console.log( res )
Or, using same variable:
let data = [ { id: "2" } , { id: "4" } ]
data = data.map(x => x.id)
console.log( data )

Map returns new array and do not alter source array. so you need to assign the result to a new variable.
const data = [{
id: "2"
}, {
id: "4"
}];
const output = data.map(function(item) {
return item.id
})
console.log(output)

Something like this? We map the key to a number and return it.
const data = [ { id: "2" } , { id: "4" } ];
var result = Object.keys(data).map(function (key) {
return Number(key);
});
console.log(result);