javascript es6 set feature

Question

I am using Set, I am able to store unique primitive values in it, but I am not able to store unique objects in it based on their property values.

Here is my sample code :

"use strict"
var set = new Set();
var student1 = {
    "name":"abc",
    "id":1
}

var student2 = {
    "name":"xyz",
    "id":1
}
var student3 = {
    "name":"def",
    "id":3
}
set.add(student1);
set.add(student2);
set.add(student3);
console.log(set);

I want to add student object in set based on theier ID values i.e. two objects will be same if the values of their ID's are same.

You can add the objects to an array first, inside that, checking duplicate `id` before adding to `Set`, Reference link: http://stackoverflow.com/questions/9229645/remove-duplicates-from-javascript-array — Tân, Oct 13 '16 at 06:13

uladzimir · Answer 1 · 2016-10-13T06:02:19.807

0

It's probably better to use Map instead for your purposes.

const map = new Map()

const student1 = {
  "name":"abc",
  "id":1
}

const student2 = {
  "name":"xyz",
  "id":1
}
const student3 = {
  "name":"def",
  "id":3
}

map.set(student1.id, student1);
map.set(student2.id, student2);
map.set(student3.id, student3);

console.log(map);

edited Oct 13 '16 at 06:02

answered Oct 13 '16 at 05:56

uladzimir

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score 0 · Answer 2 · answered Oct 13 '16 at 06:08

0

The ES6 Set object uses value equality which pretty much means === checking (as ever with Javascript there is a bit nuance here though).

As others have suggested maybe what you really want is a Map by the id attribute.

answered Oct 13 '16 at 06:08

Tom

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`Set` would never compare objects like `{ prop: val }` before adding. – Tân Oct 13 '16 at 06:17

javascript es6 set feature

2 Answers2