NodeJS vm documentation issue

[Sebi]

Hello,
I think you've a error in your docs belonging to the vm Module.
It says:

JavaScript code can be compiled and run immediately or compiled, saved, and run later. 
http://nodejs.org/docs/v0.8.1/api/vm.html#vm_executing_javascript

So if I would follow this sentence, i could do the following:

vm = require('vm');
var script = vm.createScript("hello = 'Hello World!'");
// save the script???
... JSON.stringify(script);

OUTPUT: '{}'

So how to save compiled Javascript? There is no entry in the API Docs, that describe saving compiled code.
I think until today it's an error, so the sentence should be:

Javascript can be compiled and run immediatley or compiled and run later.

[mscdex]

On Jun 29, 8:46 pm, Sebi <sebastian.tild...@googlemail.com> wrote:
> Hello,
> I think you've a error in your docs belonging to the vm Module.

What the documentation means is that you can save the actual compiled
code (into a variable) and use it again later, unlike say eval(),
which compiles code every time it's called.

[mscdex]

Additionally, the value being returned by the VM functions is a v8
context and not some magical thing that you can .toString() or similar
to get the original code back out of it.

[mscdex]

On Jun 29, 9:43 pm, mscdex <msc...@gmail.com> wrote:
> Additionally, the value being returned by the VM functions is a v8
> context and not some magical thing that you can .toString() or similar
> to get the original code back out of it.

Oops, mistook createScript() for createContext() here.

[Brandon Benvie]

It's not wrong but it is an "eats shoots and leaves" ambiguous wording that, to me at least, has the more obvious interpretation as the wrong one. You can "save" a vm script or context like you save any other value in the js heap: keep the engine running and keep a reference to it. But you cannot usefully serialize it for storage for loading later in a separate instance of the vm, aside from saving the raw input source code.