Why does eval() exist?

Question

Many programmers say it is a bad practice to use the eval() function:

When is JavaScript's eval() not evil?

Answer 1

The eval() feature is like scissors. You're an adult, it's your responsibility to not run with them.

I've seen the design philosophy of dynamic languages (like JavaScript) summarised as preferring to enable smart people to do clever things above trying to prevent stupid people from doing silly things. (Unfortunately I can't recall the original source or phrasing.)

If you're worried about introducing bugs with eval, you can use strict mode. It seems to prevent some of the problems with how the feature is designed. (That is, as a "magic" function allowed to clobber your namespace.)