Como compilar a classe JavaScript para funcionar

// Base "class":
class Base {
    // The code for `Base` goes in this special `constructor` pseudo-method:
    constructor() {
        this.baseProp = 42;
    }

    // A method to put on the `prototype` object (an "instance method"):
    baseMethod() {
        console.log(this.baseProp);
    }

    // A method to put on the constructor (a "static method"):
    static foo() {
        console.log("This is foo");
    }
}

// Derived "class":
class Derived extends Base {
//            ^------------------ defines the prototype behind `Derived.prototype`
    // The code for `Derived`:
    constructor() {
        // Call super constructor (`Base`) to initialize `Base`'s stuff:
        super();

        // Properties to initialize when called:
        this.derivedProp = "the answer";
    }

    // Overridden instance method:
    baseMethod() {
        // Supercall to `baseMethod`:
        super.baseMethod();

        // ...
        console.log("new stuff");
    }

    // Another instance method:
    derivedMethod() {
        this.baseMethod();
        console.log(this.derivedProp);
    }
}
lucky shark