in this paper: https://ieeexplore.ieee.org/document/7958598, the authors said that javascript is crash-safe and type-safe. they said crash-safe means it will never hard crash. what is the difference of crash and hard crash in javascript? what does hard crash mean in javascript? why javascript is crash-safe?
also in javascript 2+”2″ can be done without any trouble. so why javascript is type-safe? I always know javascript as type-unsafe?