Seatbelts on!

seatbelt.js

const { log } = console;

const Undefined = new Proxy(function() {}, {
  get(target, key, receiver) {
    if (key === 'name') {
      return 'Undefined';
    }

    return Undefined;
  },
  apply() {
    return Undefined;
  },
});

function seatbelt(obj) {
  return new Proxy(obj, {
    get(target, key) {
      const accessedProperty = Reflect.get(target, key);

      if (typeof accessedProperty === 'object') {
        return seatbelt(accessedProperty);
      } else {
        return accessedProperty ? Reflect.get(target, key) : Undefined;
      }
    }
  });
}

const neverUndefined = seatbelt({
  foo: 'bar',
  baz: {
    qux: 10,
  },
});

log(neverUndefined.foo)
// bar
log(neverUndefined.baz.qux)
// 10
log(neverUndefined.baz.fjsdf.fds.fds.fd.sfs.df)
// [Function: Undefined]
log(neverUndefined.b.c.d.e.sa.fd.fd.f.ds.reg.s.fd.sa.s()()()()()()().f.gf.ggf.dgdf.fgd.gfd.fdg()()()().fdfsdfsd)
// [Function: Undefined]

/**
 * Why can't I do this??? 🤔
 */
Object.prototype = seatbelt({});