JavaScript sets and value objects [duplicate]

Question

This question already has an answer here:

• user defined object equality for a set in harmony (es6) 2 answers

I want to create a set of value objects in JavaScript. The problem is that in JavaScript equality is based on identity. Hence, two different objects with the same value will be treated as unequal:

var objects = new Set;

objects.add({ a: 1 });
objects.add({ a: 1 });

alert(objects.size);   // expected 1, actual 2

How do you work around this problem?

Answer 1

Use JSON.stringify:

var objects = new Set;

objects.add(JSON.stringify({ a: 1 }));
objects.add(JSON.stringify({ a: 1 }));

alert(objects.size);