How do I use a static variable in ES6 class?

Question

I\'m trying to use a static variable in es6. I\'d like to declare a static variable count in Animal class and increase it. However, I couldn\'t declare

Answer 1

you can use closures to simulate static variables

const Animal= (() => {
    let count= 0;

    class Animal {
        constructor() {}

        static increaseCount() {
            count += 1;
        }

        static getCount() {
            return count;
        }
    }

    return Animal;
})();

console.log(Animal.getCount());
Animal.increaseCount();
console.log(Animal.getCount());