Remove duplicate from array

Question

I want to remove each copy of object from array:

  const object = [
    { label: "SUA", value: "sua" },
    { label: "SUA", value: "sua" },
    { label: "Florida", value: "florida" }
  ];
  console.log(object.map(i=> [...new Set(i)]))

At the end i have to get like:

const object = [
    { label: "Florida", value: "florida" }
  ];

How to do this in my code?

Does this answer your question? [Set of objects in javascript](https://stackoverflow.com/questions/5657219/set-of-objects-in-javascript) — Adam Azad, Oct 28 '20 at 06:43
Does this answer your question? [Remove duplicates from an array of objects in JavaScript](https://stackoverflow.com/questions/2218999/remove-duplicates-from-an-array-of-objects-in-javascript) — Sarun UK, Oct 28 '20 at 06:43
It's really not so clear what you are asking. Are you sure the end result shouldn't be: `[{ label: "SUA", value: "sua" }, { label: "Florida", value: "florida" }] instead of just the florida object? — kaan_a, Oct 28 '20 at 06:48
You need to have better test cases and problem is not clear what you are trying to solve. [ { label: "SUA2", value: "sua2" }, { label: "SUA", value: "sua" }, { label: "Florida", value: "florida" }, { label: "SUA", value: "sua" }, ] what is your expected result? — Tom, Oct 28 '20 at 07:15
@Phil I think because there was two of it, and all of them got removed — FZs, Oct 28 '20 at 07:29
@UKS I don't think so. Appearently, the OP wants to remove all occurrences of duplicates... — FZs, Oct 28 '20 at 07:31

score 0 · Answer 1 · answered Oct 28 '20 at 06:50

You can use 2 for loops to achieve your functionality.

let result = [];
for(let i=0;i<object.length ;i++) {
    let isDuplicate = false;
    for(let j=0; j<object.length;j++) {
        if(object[i].label === object[j].label && object[i].value === object[j].value && i !== j) {
            isDuplicate = true;   
        }
    }
    if(!isDuplicate) result.push(object[i]);
}

score 0 · Answer 2 · answered Oct 28 '20 at 06:54

Regardless of how many copies of each element you'd like to keep in the array, create a Map by definition Map<Location, number> and tabulate the number of occurrences of each Location object. Afterwards, take each element and append it to an array only once.


type Location = {label: string, value: string};

const object: Location[] = [
    { label: "SUA", value: "sua" },
    { label: "SUA", value: "sua" },
    { label: "Florida", value: "florida" }
];
const objects: Map<Location, number> = new Map();

for (const location of object)
    if (objects.has(location))
        objects.set(location, objects.get(location) + 1);
    else
        objects.set(location, 1);

const filtered: Location[] = [];

for (const location of objects)
    if (location[1] === 1) // You change 1 to any value depending on how many copies of each you'd like.
        filtered.push(location[0];

Note This is TypeScript for clarity, but the concept is the same.

Baruch Mashasha · Answer 3 · 2020-10-28T07:07:09.833

0

Short way:

const object = [
  { label: "SUA", value: "sua" },
  { label: "SUA", value: "sua" },
  { label: "Florida", value: "florida" }
];

const a = object.filter((v, i, a) => a.findIndex(t => (t.label === 
v.label && t.value === v.value)) === i);

console.log(a);

edited Oct 28 '20 at 07:07

answered Oct 28 '20 at 06:59

Baruch Mashasha

951
1
11
29

it would fail on object = [ { label: "SUA", value: "sua" }, { label: "SUA", value: "sua" }, { label: "Florida", value: "florida" }, { label: "SUA", value: "sua" }, ]; a = object.filter((v, i, a) => a.findIndex(t => (t.label === v.label && t.value === v.value)) === i); – Tom Oct 28 '20 at 07:13
No, you wrong it not fail, you can check it before you wrote a comment @Tom – Baruch Mashasha Oct 28 '20 at 07:16
it's wrong because he wanted to remove all the duplicated objs. – Tom Oct 30 '20 at 03:08

score 0 · Answer 4 · answered Oct 28 '20 at 07:01

0

You can use ES6 set -

const unique = [...new Set(object.map(({value}) => value))].map(e => object.find(({value}) => value == e));

console.log("unique",unique);

//[{label: "SUA", value: "sua"},{label: "Florida", value: "florida"}]

for your problem you can simply use reduce -

const uniq =  object.reduce((a,b)=>{return a.value === b.value ? {} :[b]},[])

console.log(uniq);

//[{label: "Florida", value: "florida"}]

answered Oct 28 '20 at 07:01

ganesh singh

41
4

object = [ { label: "SUA2", value: "sua2" }, { label: "SUA", value: "sua" }, { label: "Florida", value: "florida" }, { label: "SUA", value: "sua" }, ]; uniq = object.reduce((a,b)=>{return a.value === b.value ? {} :[b]},[]) // {label: "SUA", value: "sua"} ???? how would this work?? – Tom Oct 28 '20 at 07:12

score -1 · Answer 5 · answered Oct 28 '20 at 07:08

-1

Simple solution with lodash

const object = [
    { label: "SUA", value: "sua" },
    { label: "SUA", value: "sua" },
    { label: "Florida", value: "florida" }
  ];

result = _.xor(_.uniqWith(object,_.isEqual),object)

answered Oct 28 '20 at 07:08

Tom

81
5

Remove duplicate from array

5 Answers5