function pathBuilder(src, path) {

    path = path || [];

    src = src || {};

    return new Proxy(src, {

        get: function (target, name) {

            function isenum(name) {// is property enumerable, including inherited props

                for (var n in src) {

                    if (n === name) return true;

                }

                return false;

            }

​

            var val;

            if (isenum(name)) {

                val = ({}).valueOf.call(src[name]); // converting primitive type to object

            }

            else if (!(name in src)) {

                val = {};

            }

            else {

                return src[name];

            }

            path.push({

                obj: src,

                prop: name

            });

            return pathBuilder(val, path);

        },

        set: function (target, name, val) {

            src[name] = val;

            var p, current = src;

            while (path.length) {

                p = path.pop();

                p.obj[p.prop] = current;

                current = p.obj;

            }

        }

    });

}

​

​

var o1 = {};

var o2 = {someprop: 'sdasdasd'};

var p1 = pathBuilder(o1);

var p2 = pathBuilder(o2);

​

p1.a.b.c = 12;

console.log(o1);

console.log(JSON.stringify(o1)); // {"a":{"b":{"c":12}}}

​

p2.someprop.foo.bar = 'value';

console.log(o2); // someprop converts from primitive string to String object

                 // to perform assignment of foo property

console.log(p2.someprop.foo.bar);// "value"

console.log(JSON.stringify(o2)); // {"someprop":"sdasdasd"}