No, unfortunately. If a reference isn't found in your context object, it falls through to the ambient namespace. So say you run ...

    context = { foo: 1, bar: 2 };

    with (context) {
        foo = 2;
        bar = 3;
    }

That will probably do what you expect. But now say you run it where context is just ...

    context = { foo: 1 };

    with (context) {
        foo = 2;
        bar = 3;
    }

... you might think this would add a 'bar' property to your context object, but in fact it creates a global variable bar. Whoops!

In short, 'with' is pointy on both ends.

Oh yeah, `with` is dangerous.

Yep, I'm using something very like this in a Node project I'm working on. However, with(context) has some pretty nasty side effects that I just couldn't sidestep, so I used the "contextify" module.

If you're needing with and have access to npm, use contextify, It'll save you a lot of effort!

Thanks for the tip, but I'm far from working with javascript right now[1], I was barely trying to understand the trick. I love the fact that this 'app' is a 6x6 variables grid layout javascript editor in disguise.

[1] I just finished skimming through eloquent js and js allonge, and this still eluded me.

Do you mind elaborating on those nasty side effects? (I use with(context) for a small but important feature in the product I work on.)

if it's on node.js I imagine there's things to worry about like malicious injection