CODEWITHSUNDEEP
javascriptecmascript-6generatoryield
Slavik Meltser
Slavik Meltser

Reputation: 10371

Best practice for passing through generator function in JS

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?

Upvotes: 0

Views: 97

Answers (1)

Ry-
Ry-

Reputation: 225005

  1. How do I passthrough a return in addition to yield?
* generate() {
    return yield* this.service.generate();
}
  1. Is there a better and more clean way to implement it?
generate() {
    return this.service.generate();
}

    #service;

this.#service = …

return this.#service.generate();

Upvotes: 1

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