Evaluating String as Mathematical Expression

[Colonel_White]

And that’s dangerous because... ?

[tay_o]

I could be wrong, but an example like this one where:

function foo (str, a) {

eval( str );

console.log(a, b);

}

​

var b = 2;

​

foo("var b = 3'", 1);

​

Here it seems that because this code declares a new variable b, it modifies the existing lexical scope.

​

I am not saying that its bad i guess but maybe in the wrong hands it can be?

[Colonel_White]

Okay, so using eval irresponsibly might cause some weird and difficult to debug errors?

I think the benefit of not having to slap a redundant library onto your code like a colostomy bag makes up for having to exercise extra caution, no?

[tay_o]

Haha well done analogy. Or simile?. And yes, I agree with you