Subj : Re: "deprecated with statement usage"
To   : bmf1972@icqmail.com
From : Igor Bukanov <igor@fastmail.fm>
Date : Tue Oct 14 2003 04:46 pm

Adrian Herscu wrote:
> Why it is deprecated?
> Is it safe to use it?

> Does it have any hidden (or hardly to anticipate) behaviors?

If x does not have the property y, then the following code

with(x) { y = 10; }

will not add a new property y to the object x and instead will define a 
new global variable y. But if the prototype object for x contains 
property y, then x will get y. Now consider maintenance nightmare when 
the object x or its prototype gain or lose properties.

In addition "with" is very costly syntax sugar since its mere existence 
makes JavaScript implementation significantly more complex and prevents 
many possible optimizations.

Regards, Igor.

.