Generic property get set adder

setup_property.js

function setupProperty(obj, prop, setcb) {
    Object.defineProperty(obj, prop, {
        get: function() {
            return obj['__'+prop];
        },
        set: function(v) {
            console.log(prop);
            obj['__'+prop] = v;

            if (setcb) setcb(v);
        }
    });
}

// Use
setupProperty(obj, 'my_prop', function (v) {
    // ... set sub property of v
})