Set of objects in javascript

I’d like to have a set of objects in Javascript. That is, a data structure that contains only unique objects.

Normally using properties is recommended, e.g. myset["key"] = true. However, I need the keys to be objects. I’ve read that Javascript casts property names to strings, so I guess I can’t use myset[myobject] = true.

I could use an array, but I need something better than O(n) performance for adding, finding and removing items.

It needs to be able to tell objects apart by reference only, so given:

var a = {};
var b = {};

then both a and b should be able to be added, because they’re separate objects.

Basically, I’m after something like C++’s std::set, that can store Javascript objects. Any ideas?

Answer

ES6 provides a native Set:

let s = new Set();
let a = {};
let b = {};

s.add(a);

console.log(s.has(a));  // true
console.log(s.has(b));  // false

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Answer