The eval function is a way to run arbitrary code at run-time. Dynamically evaluating code is slow and a potential security issue when
the arguments haven't been properly validated.
In general it is better to avoid it altogether, particularly when there are safer alternatives.
var value = eval('obj.' + propName); // Noncompliant
var value = obj[propName];
This rule will not raise an issue when the argument of the eval call is a literal string as it is reasonably safe.