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How to get unique value of keys from array of object using javascript?

By : Albert KH
Date : October 15 2020, 08:10 AM
Does that help use Array.map for get all car values and use Array.filter for filter duplicate car values, you can do it by chaining Array.map().filter()
code :
var arr = [{
    "name": "John",
    "age": 30,
    "cars": "BMW"
    "name": "Micheal",
    "age": 30,
    "cars": "Ford"
    "name": "Andy",
    "age": 29,
    "cars": "Ford"

var carValues = arr.map( (value) => value.cars).filter( (value, index, _arr) => _arr.indexOf(value) == index);

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Array Unique for Array of Objects with exclude option for certain keys in Object

By : Manesh
Date : March 29 2020, 07:55 AM
I think the issue was by ths following , See also array_unique for objects?
In case you work with non-stdClass object you could implement __toString to use array_unique to filter.
code :
array_unique(array_map(function($item) {return $item->payrate;},$array);
$attributes = ['payrate','date']
$filtered = array_reduce($array,function($carry,$item) use ($attributes) {
    if(count(array_filter($attributes,function ($attribute) use ($carry, $item) {
            return !in_array($item->$attribute,array_map(function($carriedItem) use ($attribute) {
                return $carriedItem->$attribute;
        }))) {
        $carry[] = $item;
    return $carry;

Get unique keys only from javascript array, where keys and value both are dynamic

By : Laurentiu
Date : March 29 2020, 07:55 AM
it helps some times I will make a temp object storing the last found values and then create the resulting array.
code :
let tempObj = {}

let srcArray = [

for (let item of srcArray) {
  tempObj[item.index] = item.name

let result = Object.keys(tempObj).map(index => {
  return {
    name: tempObj[index]


Convert a key-value array with duplicate keys into array of object with unique key, and value array property

By : anant
Date : March 29 2020, 07:55 AM
this one helps. You can simply create a map using Array.reduce() with your key property of your object as key of your map, Object.values() on that map will give you the desired result :
Assuming you have a typo in your expected output. You can try the following :
code :
let pairArray =  [ { key: "a", value: "1" }, { key: "a", value: "2" }, { key: "b", value: "1" }, { key: "b", value: "2" }, ];

let result = Object.values(pairArray.reduce((acc, {key, value})=>{
  acc[key] = acc[key] || {key, values : []};
  return acc;


Is it possible in JavaScript to get unique references to unique DOM elements (for use as unique keys in an object)?

By : Anthony Spackman
Date : March 29 2020, 07:55 AM
wish help you to fix your issue WeakMap's are really handy for this.
There similar to Map's, but will get removed & garbage collected when the Element is destroyed.
code :
const data = new WeakMap();

let count = 0;
for (const el of document.querySelectorAll("div")) {
  count += 1;
  data.set(el, `This is data for item ${count}`);

document.body.addEventListener("click", evt => {
  const info = data.get(evt.target);
  if (info) document.querySelector("#clicked").innerText = info;
div { 
  border: 1px solid black; 
  padding: 4px;
  margin: 4px;
<div id="items">
<div id="clicked"></div>

Unique object literal keys- javascript

By : abu rafe md jamil
Date : March 29 2020, 07:55 AM
This might help you , You must call obj like an Array
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