Best practice for passing through generator function in JS

Question

I am trying to figure out the best practice of passing a generator (including yield) function through another function as is.

In other words, I am looking for a better way to achieve the following.

Let's say that I have class ServiceA and ServiceB , that own the same method generate , that generates some sequences:

class ServiceA extends ServiceBase {
    // ...

    * generate() {
        const length = Math.round(Math.rand() * 100);
        for (let i=0; i<length; i++)
            yield i;
        return -1;
    }

    // ...
}

class ServiceB extends ServiceBase {
    // ...

    * generate() {
        const length = Math.round(Math.rand() * 100) + 100;
        for (let i=100; i<length; i++)
            yield i;
        return 13;
    }

    // ...
}

Now, I have a wrapper class ServiceName that uses class ServiceA or ServiceB , but also, passing through the generate method from these classes:

class ServiceManager {
    #service;

    constructor(serviceName) {
        // The following require will return ServiceA or ServiceB instance
        this.#service = require('./service/' + serviceName);
    }

    * generate() {
        for ( let i of this.#service.generate() )
            yield i;
    }

    // ...
}

And extension is not an option, as this is a design pattern I need.

Two questions regarding the generate method within class ServiceManager :

1. How do I passthrough a return in addition to yield ?
2. Is there a better and more clean way to implement it?

Answer 1

1. How do I passthrough a return in addition to yield ?

* generate() {
    return yield* this.service.generate();
}

2. Is there a better and more clean way to implement it?

generate() {
    return this.service.generate();
}

 #service;

this.#service = …

return this.#service.generate();