node-inspector: A JavaScript repository from asnowfix

Node Inspector is a debugger interface for nodeJS using the WebKit Web Inspector.

Getting Started

Requirements

nodeJS
- versions: 0.3.0 or later
npm
A WebKit based browser: Chrome, Safari, etc.
Optional v8-profiler to use the profiles panel

Install

With npm
```
  $ npm install -g node-inspector
```

Enable debug mode

To use node-inspector, enable debugging on the node you wish to debug. You can either start node with a debug flag like:

$ node --debug your/node/program.js

or, to pause your script on the first line:

$ node --debug-brk your/short/node/script.js

Or you can enable debugging on a node that is already running by sending it a signal:

Get the PID of the node process using your favorite method. pgrep or ps -ef are good
```
 $ pgrep -l node
 2345 node your/node/server.js
```
Send it the USR1 signal
```
 $ kill -s USR1 2345
```

Great! Now you are ready to attach node-inspector

Debugging

start the inspector. I usually put it in the background
```
 $ node-inspector &
```
open http://127.0.0.1:8080/debug?port=5858 in your favorite WebKit based browser
you should now see the javascript source from node. If you don't, click the scripts tab.
select a script and set some breakpoints (far left line numbers)
then watch the screencasts

For more information on getting started see the wiki

node-inspector works almost exactly like the web inspector in Safari and Chrome. Here's a good overview of the UI

FAQ / WTF

I don't see one of my script files in the file list.

try refreshing the browser (F5 or command-r)
My script runs too fast to attach the debugger.

use --debug-brk to pause the script on the first line
I got the ui in a weird state.

when in doubt, refresh
Can I debug remotely?

Yes. node-inspector must be running on the same machine, but your browser can be anywhere. Just make sure port 8080 is accessible

Inspector options

--web-port=[port]     port to host the inspector (default 8080)

Cool stuff

the WebKit Web Inspector debugger is a great js debugger interface, it works just as well for node
uses WebSockets, so no polling for breaks
remote debugging
javascript top to bottom :)
edit running code

Known Issues

This is beta quality code, so use at your own risk:

be careful about viewing the contents of Buffer objects, each byte is displayed as an individual array element, for anything but tiny Buffers this will take too long to render
while not stopped at a breakpoint the console doesn't always behave as you might expect

Profiling

VERY EXPERIMENTAL I don't recommend using this yet

To use the profiles panel, install the v8-profiler module:

npm install v8-profiler

To use it do something like:

var profiler = require('v8-profiler');

profiler.startProfiling('startup');
slowStartupFoo();
profiler.stopProfiling('startup');

profiler.takeSnapshot('beforeLeak');
leakyFoo();
profiler.takeSnapshot('afterLeak');

Then view the profiling results with the profiles panel in node-inspector. You can also take heap snapshots on demand from the profiles panel.

Thanks

This project respectfully uses code from and thanks the authors of:

asnowfix/node-inspector