Execution hooks

[Deepak Subramanian]

Hi,

When a JS is executing in v8. I would like to know which line it is.

eg.

function f1()

{

print - line 1 starting

expr;

print -line 1 ended

print- line 2 starting

expt;

print -line 2 ended

..

}

Any pointers are highly appreciated.

Thanks

Best Regards,

Deepak Subramanian

[Ben Noordhuis]

On Thu, Oct 22, 2015 at 3:21 PM, Deepak Subramanian
<subud...@gmail.com> wrote:
> Hi,
>
> When a JS is executing in v8. I would like to know which line it is.
>
> eg.
>
> function f1()
> {
> print - line 1 starting
> expr;
> print -line 1 ended
> print- line 2 starting
> expt;
> print -line 2 ended
> ..
> }
>
> Any pointers are highly appreciated.

You can step through the code using the debug API. Pass
--expose_debug_as=debug and check src/debug/debug.js for step actions.
You'll need to install a debug event listener first with
debug.Debug.setListener().

[Deepak Subramanian]

Thanks a lot. 

Could you give me a very short sample of a debugListener.

Thanks again

[Ben Noordhuis]

On Mon, Oct 26, 2015 at 10:06 AM, Deepak Subramanian
<subud...@gmail.com> wrote:
> Could you give me a very short sample of a debugListener.

A very simple example:

// Flags: --expose_debug_as=debug
debug.Debug.setListener(listener);
debug.Debug.setBreakPoint(main);
main();

function listener(evt, state, info) {
if (evt !== debug.Debug.DebugEvent.Break) return;
state.prepareStep(); // defaults to StepIn
}

function main() {
// main program goes here
}