Immutable

Immutable allows us to generate constructors that validate schema's, using Blueprint, and to render immutable objects.

im•mu•ta•ble (ĭ-myo͞oˈtə-bəl), adj. Not subject or susceptible to change.

When out objects are subject to change, side effects can cause problems. Making our objects immutable, and achieving the Open/Closed Principle in JavaScript can be verbose. polyn's Immutable makes this trivial.