Javascript ES6 shared class variable

Question

I have a class that looks like this:

class Foo {
    constructor(arg1, arg2) {
        // ...

        this._some_obj = new SomeObj({
            param1: arg1,
            param2: arg2
        });
    }

    // ...
}

module.exports = Foo;

Now I want to do the same thing but with _some_obj shared between all instances of the class.

After searching around I'm unclear as to the correct way to do this in ES6.

Answer 1

As known from ES5, you can just put it on the class's prototype object:

export class Foo {
    constructor(arg1, arg2) {
        …
    }
    …
}
Foo.prototype._some_obj = new SomeObj({
    param1: val1,
    param2: val2
});

Or directly on Foo, if you don't need to access it as a property on instances.