Example impl

gistfile1.txt

import util from 'util';

function hypotheticalDecoratorThatMerges(target, key, descriptor)
{
    let result = descriptor;
    
    if ('get' in descriptor || 'set' in descriptor)
    {   
        const desc = {}; 
        Object.keys(descriptor).forEach(
        function (k) 
        {   
            desc[k] = descriptor[k];
        }); 
        
        let superclass;
        let supertarget;
        if (typeof target == 'function')
        {   
            superclass = Object.getPrototypeOf(target);
            supertarget = superclass;
        }   
        else
        {   
            superclass = Object.getPrototypeOf(target.constructor);
            supertarget = superclass.prototype;
        }   

        let superdesc = Object.getOwnPropertyDescriptor(supertarget, key);

        if (!descriptor.set && superdesc.set)
        {   
            desc.set = function (v) { superdesc.set.apply(this, v); };
        }   
        if (!descriptor.get && superdesc.get)
        {   
            desc.get = function () { return superdesc.get.apply(this); };
        }   

        desc.enumerable = desc.enumerable && superdesc.enumerable;
        desc.configurable = desc.enumerable && superdesc.configurable;

        console.log(util.inspect(superdesc));
        console.log(util.inspect(desc));
        
        result = desc;
    }   
    
    return result;
}

export class Base
{
     get name() {}
     set name(v) {}
}

export class Derived extends Base
{
    @hypotheticalDecoratorThatMerges
    set name(v) {}
}