How do I debug Node.js applications?

Question

How do I debug a Node.js server application?

Right now I'm mostly using alert debugging with print statements like this:

sys.puts(sys.inspect(someVariable));

There must be a better way to debug. I know that Google Chrome has a command-line debugger. Is this debugger available for Node.js as well?

Answer 1

node-debug -p 8888 scriptFileName.js

Answer 2

I personally use JetBrains WebStorm as it's the only JavaScript IDE that I've found which is great for both frontend and backend JavaScript.

It works on multiple OS's and has Node.js debugging built-in (as well as a ton of other stuff](http://www.jetbrains.com/webstorm/features/index.html).

My only 'issues'/wishlist items are were:

1. It seems to be more resource hungry on Mac than Windows It no longer seems an issue in version 6.
2. It would be nice if it had Snippet support (like those of Sublime Text 2 - i.e. type 'fun' and tap 'tab' to put in a function. See @WickyNilliams comment below - With Live Templates you also have snippet support.

Answer 3

I wrote a different approach to debug Node.js code which is stable and is extremely simple. It is available at https://github.com/s-a/iron-node.

An opensource cross-platform visual debugger.

Installation:

npm install iron-node -g;

Debug:

iron-node yourscript.js;

Answer 4

Using Chrome Version 67.0.3396.62(+)

1. Run node app

node --inspect-brk=0.0.0.0:9229 server.js(server js filename)

2. Browse your app in chrome e.g. "localhost:port"
3. Open DevTools.
4. Click the the node icon beside the responsive device icon.

There will be another DevTools window that will pop out specifically for debugging node app.

Answer 5

Visual Studio Code will be my choice for debugging. No overhead of installing any tools or npm install stuff. Just set the starting point of your app in package.json and VSCode will automatically create a configuration file inside your solution. It's build on Electron, on which editors like Atom are built.

VS Code gives similar debugging experience as you might have had in other IDEs like VS, Eclipse, etc.

Answer 6

Node.js Tools for Visual Studio 2012 or 2013 includes a debugger. The overview here states "Node.js Tools for Visual Studio includes complete support for debugging node apps.". Being new to Node.js, but having a background in .NET, I've found this add in to be a great way to debug Node.js applications.