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Optimal way to find union of two data sets

I am working on a side project where I am comparing two different databases and want to find the common elements of the data sets based on the "id" field. I want to know if there is an optimal solution instead of using two nested for loops. Is there a way to do it with a hash map? Many Thanks!
Below is the sample code I am working with.
UPDATE all ids are unique with no possibility of there being a duplicate
// data set 1
const set1 = [
{
id: "001",
name: "bob",
age: "50",
location: "texas"
},
{
id: "002",
name: "bill",
age: "51",
location: "texas"
},
{
id: "003",
name: "ben",
age: "52",
location: "texas"
},
{
id: "004",
name: "cam",
age: "53",
location: "texas"
},
{
id: "005",
name: "max",
age: "54",
location: "texas"
}
]
// data set 2
const set2 = [
{
id: "001",
name: "bob"
},
{
id: "002",
name: "bill"
}
]
// I want to create a function where I find the the common elements of the two lists based on id and put the common element of data set 1 into a list and return that list
const findUnion(set1, set2) {
// logic here, I know I can do a nested for loop but is there a more efficient way such as
// using a hashmap? ( Map() object? )
}
// desired output
const output = [
{
id: "001",
name: "bob",
age: "50",
location: "texas"
},
{
id: "002",
name: "bill",
age: "51",
location: "texas"
}
]

You can use Sets for efficient lookup:
const ids1 = new Set(set1.map(({id}) => id));
const ids2 = new Set(set2.map(({id}) => id));
const output = set1.filter(({id}) => ids1.has(id) && ids2.has(id));
console.log(output);

First of all, you're looking for the intersection, not the union.
As others have said, we can use a Set to track uniqueness. This gives us near O(1) lookup time, and allows us algorithm that runs in something like O(m + n) time where m and n are the sizes of your sets:
const intersection = (s1, s2, ids = new Set (s2 .map (x => x .id))) =>
s1 .filter (({id}) => ids .has (id))
const set1 = [{id: "001", name: "bob", age: "50", location: "texas"}, {id: "002", name: "bill", age: "51", location: "texas"}, {id: "003", name: "ben", age: "52", location: "texas"}, {id: "004", name: "cam", age: "53", location: "texas"}, {id: "005", name: "max", age: "54", location: "texas"}]
const set2 = [{id: "001", name: "bob"}, {id: "002", name: "bill"}]
console .log (intersection (set1, set2))
.as-console-wrapper {max-height: 100% !important; top: 0}

First we combine into one long array. Then group by id using reduce method. Each group contains the item and count of appearances. Finally, for each of the groups, return only those with count of appearances > 1.
Edit: fixed algorithm see code.
Edit 2: Made it more generic so order of items won't matter. This is by extending the duplicates rather then replacing them.
function findUnion(set1, set2) {
// first remove duplicates from each set
// bonus: collect duplicates
var duplicates;
function dedup(set) {
duplicates = []
return Object.values(set.reduce(function(agg, item) {
var merged = item;
if (agg[item.id]) {
merged = { ...agg[item.id],
...item
}
duplicates.push(merged)
}
agg[item.id] = merged;
return agg
}, {}));
}
set1 = dedup(set1);
set2 = dedup(set2);
// then combine
var combined = [...set1, ...set2]
// then remove duplicates again, this time keep them
dedup(combined)
return duplicates;
}
// data set 1
const set1 = [{
id: "001",
name: "bob",
age: "50",
location: "texas"
},
{
id: "002",
name: "bill",
age: "51",
location: "texas"
},
{
id: "003",
name: "ben",
age: "52",
location: "texas"
},
{
id: "004",
name: "cam",
age: "53",
location: "texas"
},
{
id: "005",
name: "max",
age: "54",
location: "texas"
},
{
id: "005",
name: "max",
age: "54",
location: "texas"
},
{
id: "005",
name: "max",
age: "54",
location: "texas"
}
]
// data set 2
const set2 = [{
id: "001",
name: "bob"
},
{
id: "002",
name: "bill"
}
]
// desired output
const output = [{
id: "001",
name: "bob",
age: "50",
location: "texas"
},
{
id: "002",
name: "bill",
age: "51",
location: "texas"
}
]
console.log(findUnion(set1, set2))

How to move the objects to the top inside array based on the matched key

I have an array of objects with different keys I want to move the objects to the top based on the key I want.
Given array based on the status: "Active" I want all the matched objects to be moved top
[
{name: "abc", age: "20", status: "Active"},
{name: "xyz", age: "21", status: "Inactive"},
{name: "pqr", age: "22", status: "Active"}
]
Expected Output:
[
{name: "abc", age: "20", status: "Active"},
{name: "pqr", age: "22", status: "Active"},
{name: "xyz", age: "21", status: "Inactive"}
]

let list = [{
name: "abc",
age: "20",
status: "Active"
}, {
name: "xyz",
age: "21",
status: "Inactive"
}, {
name: "pqr",
age: "22",
status: "Active"
}]
list.sort((a, b) => (a.status !== "Active") ? 1 : -1)
console.log(list)
Produces the following output
[
{ name: 'pqr', age: '22', status: 'Active' },
{ name: 'abc', age: '20', status: 'Active' },
{ name: 'xyz', age: '21', status: 'Inactive' }
]

you can change your code like this.
function handleData(arr, status) {
if(!arr || arr.length == 0) return
for(let i=0; i<arr.length; i++) {
let item = arr[i];
if(item.status == status) {
arr.splice(i, 1);
arr.unshift(item)
}
}
}
let arr = [{name: "abc", age: "20", status: "Active"}, {name: "xyz", age: "21", status: "Inactive"}, {name: "pqr", age: "22", status: "Active"}]
handleData(arr, 'Active')

Arrays have method Array.sort where you can pass function that return 1, -1 or 0 which corresponds to how to move element of an array
const arr = [{
name: "abc",
age: "20",
status: "Active"
}, {
name: "xyz",
age: "21",
status: "Inactive"
}, {
name: "pqr",
age: "22",
status: "Active"
}]
console.log(arr.sort((a, b) => (a.status === b.status) ? 0 : a.status === "Active" ? -1 : 1))

Javascript manipulate data into array of object for d3 stacked chart

I have:
[{ID: "1", Job: "Student", Gender: "Male", Income: 2200},
{ID: "2", Job: "Student", Gender: "Male", Income: 1300},
{ID: "3", Job: "Student", Gender: "Female", Income: 5400},
{ID: "4", Job: "Teacher", Gender: "Female", Income: 4200},
{ID: "5", Job: "Teacher", Gender: "Female", Income: 4000}]
Trying to manipulate into the below format for d3 stacked bar chart (like the data in this link) :
[{name: "Student", Male: 3500, Female: 5400},
{name: "Teacher", Male: 0, Female: 8200}]
I tried all sorts of for-loop and sums and got myself all confused, so I won't bore you with my lengthy inefficient code. How would you do it?

You can use reduce for that.
The reduce method executes a reducer function on each element of the array.
the reducer function's returned value is assigned to the accumulator (res). this value is remembered for each iteration throughout the array. the second value is the current value which we will use to figure out is this a Male/Female and add to the relatively gender income.
const data = [{ID: "1", Job: "Student", Gender: "Male", Income: 2200},
{ID: "2", Job: "Student", Gender: "Male", Income: 1300},
{ID: "3", Job: "Student", Gender: "Female", Income: 5400},
{ID: "4", Job: "Teacher", Gender: "Female", Income: 4200},
{ID: "5", Job: "Teacher", Gender: "Female", Income: 4000}];
var result = [];
data.reduce(function(res, value) {
if (!res[value.Job]) {
res[value.Job] = { name: value.Job, Male: 0, Female: 0 };
result.push(res[value.Job])
}
if (value.Gender === "Male"){
res[value.Job].Male += value.Income;
}
else{
res[value.Job].Female += value.Income;
}
return res;
}, {});
console.log(result)

I would probably do it like this for my own code. One concern might be that the get_totals_by_job function is a bit difficult to understand without some effort.
const data = [{ID: "1", Job: "Student", Gender: "Male", Income: 2200},
{ID: "2", Job: "Student", Gender: "Male", Income: 1300},
{ID: "3", Job: "Student", Gender: "Female", Income: 5400},
{ID: "4", Job: "Teacher", Gender: "Female", Income: 4200},
{ID: "5", Job: "Teacher", Gender: "Female", Income: 4000}];
const get_totals_by_job = (acc, val) => Object.assign(
acc,
{
[val.Job]: Object.assign(
acc[val.Job] || { Male: 0, Female: 0 },
{ [val.Gender]: (acc[val.Job]?.[val.Gender] || 0) + val.Income }
)
}
);
const result = Object
.entries( data.reduce(get_totals_by_job, {}) )
.map( ([name, totals]) => Object.assign({ name }, totals) );
console.log(result);

How to create a new object from array of objects?

I have the following dynamic array of objects:
[
{
id: "1"
name: "Jane"
age: 25
},
{
id: "2"
name: "John"
age: 35
},
{
id: "3"
name: "James"
age: 27
},
]
I need to create new object like this:
"peopleSelected:{
"1":
{
"name": "Jane",
"age": 25
},
"2":
{
"name": "John",
"age": 35
},
"3":
{
"name": "James",
"age": 27
},
where structure is
"id" :
{
"name":name,
"age":"age
}
and I need to save this newly created object using useState, I can't figure out how to do that. Please help.

Using Array.prototype.reduce()
const arr = [
{
id: "1",
name: "Jane",
age: 25,
},
{
id: "2",
name: "John",
age: 35,
},
{
id: "3",
name: "James",
age: 27,
},
],
solution = {
peopleSelected: arr.reduce((acc, { id, name, age }) => {
acc[id] = { name, age };
return acc;
}, {}),
};
console.log(solution);

You can use object destructuring as below:
import React from 'react';
import { useState, useEffect } from 'react';
let people = [
{
id: "1",
name: "Jane",
age: 25
},
{
id: "2",
name: "John",
age: 35
},
{
id: "3",
name: "James",
age: 27
}
];
function App() {
const [ selectedPeople, setSelectedPeople ] = useState({});
useEffect(() => {
console.log(Object.entries(people));
let extractedArray = Object.entries(people);
let result = extractedArray.map((item) => {
return `${item[1].id}: ${{
"name": item[1].name,
"age": item[1].age
}}`
})
console.log(result);
// Performing object destructuring and setting the state of selectedPeople as an object
setSelectedPeople({...people})
}, [])
return <div>
<pre>
{JSON.stringify(selectedPeople, null, '\t')}
</pre>
</div>;
}
export default App;

Filter a list based on a selection

Given the data below, I have two select lists, the first select list is to display the name of each person... the second select list is two display the name of the children of the selected person. Using lodash what is the easiest way to do this?
const people = [{
id: "1",
name: "bob",
gender: "male",
children: [{
id: "1",
name: "sarah"
}]
},
{
id: "2",
name: "tom",
gender: "male",
children: [{
id: "1",
name: "lisa"
}]
},
{
id: "3",
name: "sue",
gender: "female",
children: [{
id: "1",
name: "larry"
}]
}
]

Please find the solution as below:
import map from "lodash/map";
import partialRight from "lodash/partialRight";
import pick from "lodash/pick";
import find from "lodash/find";
const test = [
{
id: "2",
name: "tom",
gender: "male",
children: [
{
id: "1",
name: "lisa"
}
]
},
{
id: "3",
name: "sue",
gender: "female",
children: [
{
id: "1",
name: "larry"
}
]
}
];
// Person selection list
const persons = map(test, partialRight(pick, ["id", "name", "gender"]));
// Replace selected person value in `persons[0]`.
const childrens = find(test, item => item.id === persons[0].id).children;