use of "Annotations for js"

gistfile1.js

    function Human(){
        /*  @@-FirstName-
                myType:TEXT,
                myDefaultValue:John
            @@ */
        this.FirstName;
        /*  @@-LastName-
                myType:TEXT,
                myDefaultValue:Doe
            @@ */
        this.LastName;

        this.toString = function(){
            return this.FirstName+" "+this.LastName;
        }
    }
    
    var h = new Human();

    console.log(Annotations(Human));
    
    h.FirstName = Annotations(Human)['FirstName']['myDefaultValue']; /*display John*/
    h.LastName = Annotations(Human).LastName.myDefaultValue; /*display Doe*/
    console.log(h.toString());  /*display John Doe*/