How do I make a class's instances comparable and garbage collectable at the same time?

Question

I\'m writing a class and want the instances to be comparable by <, >, ==.

For < and ><

Answer 1

First of all keep in mind that == is always worse than === because of such troubles. When you use x == y comparison where both operands are objects then js will compare them as objects. (more here https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Comparison_Operators) It is easy to test just running

class ComparableObject {
  constructor(id) {
    this.id = id;
  }

  valueOf() {
    console.log("log", this.id);
    return this.id;
  }
}

new ComparableObject("12") == new ComparableObject(12);

It will not produce any log but this:

new ComparableObject("12") == new ComparableObject(12).valueOf();

will print:

log 12
log 12
true

There are few solutions for your need:

Number(new ComparableObject("12")) == Number(new ComparableObject(12));
new ComparableObject("12").valueOf() == new ComparableObject(12).valueOf();

GC cannot do something untill cache object will not remove references to instances.