#node-inspector

Download node-inspector:

Open terminal and type sudo npm install -g node-inspector

Enter the password when prompted

Note: If you encounter this exception: gyp WARN EACCES user “root” does not have permission to access the dev dir then type that command instead:

sudo npm install --unsafe-perm --verbose -g node-inspector

Run your js code with node using the debug-brk param:

node --debug-brk TestWebServer.js

Open a new terminal window and run node inspector:

node-inspector

Copy the URL

Open Chrome and run the already copied URL

There you are, Chrome opens up the javascript code you are looking to debug

Put a breakpoint in the code and issue a request, e.g. http://localhost:3000 and the debugger stops the execution at the breakpoint in the code and you can take it from there

Aug 26th 2013 Updates****

the main branch is the most current again as of Aug 20th 2013

there are also updates to the readme that include a lot what I wrote below:

1. install node-inspector

npm install -g node-inspector

2. don't use port 8080 in your node app (this port is used by node-inspector)***

3. start your app using

node --debug-brk app.js

this starts node in debugging mode with a break at line 1

4. start node inspector

node-inspector

this will output a url, open that url in your browser

5. use chrome debugging tools!!

notes:

you can use debugger or breakpoints as normal

no jasmine-node support...

this main app is no longer supported, and I suggest using the fork linked to above

autorestart node-inspector when you hit an error using these commands:

until node-inspector; sleep 1; done

*** if you want to use port 8080 for your node server you can change the port that node-inspector uses

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

**** Updated from:

as of july 2013 this fork is the best: strongloop/node-inspector

Lately I've been playing with Cloud9IDE and test driving the development as a service concept (DaaS). While the Cloud9IDE is far from being bulletproof it's showing signs of greatness. As a comparison I figured I should share how I debug my node app before learning about Cloud9IDE.  I should note that this is still my preferred method.

Enter node-inspector, a tool that allows one to remotely debug node applications directly from a webkit enabled browser (safari/chrome). Unlike Cloud9IDE, node-inspector focuses exclusively on debugging. This isn't a huge issue for me as Komodo allows me to remotely edit files whereby sparing me from edit / deploy cycles.

Let's briefly examine what node-inspector offers.

In the upper left panel you can navigate source files. In this example, I've set a breakpoint on line 19 in a file called router.js. In the lower panel is the console view. I've typed "map" in order to view the contents of the map variable. The panel on the right also shows variables which are currently in scope. The upper right panel features the call stack which allows you to switch stack frames.

I still get a kick out of debugging client-side using FireBug and server-side using Node-Inspector. As a side note node-inspector is a good way of learning more about the node.js runtime environment.

Getting started with node-inspector is quick and painless.

Installation

First make sure you have the Node Package Manager (npm) installed.

Next, install node-inspector on the machine where your node.js application will run.

$ npm install -g node-inspector

Using node-inspector

Start node-inspector.

$ node-inspector &

Lastly, start your node.js application in debug mode.

$ node --debug server.js

You can then access the node-inspector via your web browser by accessing your machine via the default port of 8080.  Once the page loads you can select the script you'd like to debug. 

Today I had another mind-blowing experience.

As I was writing a software project in Node, which has reached it's critical level for me, where I just don't want to go on, with sys.puts and sys.inspect to find out, what my code is doing, I was in search of a Debugger for node.

Yesterday I tried out Cloud9's Javscript IDE, but while being really a great project, is still in the very beginnings and I wasn't able to set breakpoints in Chrome nor in Firefox. Perhaps I was doing something wrong, but it just didn't work out of the box for me and I couldn't find any documentaion yet. Anyways, Cloud9 is going to be really a great IDE some day!

So I was tinkering around and remembered, that I came accross a link to a project that involves Webkit's Web Inspector as a debugger for Node.js. The Project is called Node- Inspector.

A npm install node-inspector gave me a good start and I got all that was necessary on my system.

Node-Inspector itsself is written in Javascript as it should be and runs with node. ;) The way node-inspector works is that it spawns a Webserver on port 8080 by default, where you can see Web Inspectors debugger Interface. Then it connects to Node's Debug port, which in my case is 5858.

There is some confusion in the Readme and the screencast of how to startup node-inspector.

However a fast node --help, made things clear.

So here is my Installation Instruction:

Start node-inspector, by typing: node-inspector& (this will start the Webserver)

Startup your favourite Webkit browser (e.g. Safari, Chrome, etc) and go to 127.0.0.1:8080

start node with the --debug-brk option. This will start a TCP debug port at 5858 and set a startup breakpoint on the first line of your Javascript file.

So if youR Javascript file is called "hello.js".

node --debug-brk hello.js will startup things.

Now go back to your browser and hit the "Connect to Node" button.

all your node are belong to us now!

Web Inspector is about the greatest debugger around and seeing it full screen debugging node is just mind-blowing cool!