> If a function is "referentially transparent" or "pure" it can't do anything unexpected. Sure it can; at a minimum all functions consume compute resources. A

> If a function is "referentially transparent" or "pure" it can't do anything unexpected. Sure it can; at a minimum all functions consume compute resources. A tiny change in a "pure" JavaScript function could lead to cascading deoptimizations that destroys performance and compromises service availability. For example, changing 0.0 to 0 could do it.